Bookmarks    
nPr and nCr    
Random Number    
SD Calculator    
Sample Size    
Percent Error    
Density    
Molarity    
Molar Mass    
Ohm's Law    
Watts to Amps    
Voltage Drop    
Long Division    
Mixed Numbers    
Rounding    
Nth Root    
Exponents    
Half-Life    
Polar Form    
De Moivre    
3D Distance    
Point to Line    
Cross Product    
Determinant    
Sin Cos Tan    
Triangle Area    
Scale Factor    
Sector Area    
Ellipse Area    
Cube Volume    
Box Volume    
Sphere Volume    
Cone Volume    
Pipe Volume    
Time Duration    
Time Card    
Present Value    
Future Value    
Churn Rate    
A/B Test Calc    
SEO Traffic    
Ideal Weight    
Fat Intake    
Child Height    
Golf Handicap    
Heat Index    
Wind Chill    
Dew Point    
Download Time    
kWh to Cost    
AC Size (BTU)    
Heating Costs    
LED Savings    
Trip Gas Cost    
Tire Size    
Solar Output    
Solar Payback    
Battery Size    
Wall Area    
Gravel Needed    
Mortar Mix    
Slope Grade    
Curtain Size    
Soil Needed    
Sod Needed    
Ramp Length    
Blind Size    
Drain Slope    
Board Feet    
Heat Loss    
Furniture Fit    
Moving Boxes    
Plywood Cuts    
Shelf Sag    
   Add
Probability and random number calculators
Independent Events
Independent Events
Two Events Solver
Two Events Solver
Repeated Trials
Repeated Trials
Bayes' Theorem
Bayes' Theorem
Expected Value
Expected Value
Binomial Distribution
Binomial Distribution
nPr and nCr
nPr and nCr
Circular Permutation
Circular Permutation
With Repetition
With Repetition
Random Number
Random Number
Averages and statistics calculators
Average Calculator
Average Calculator
Mean Median Mode
Mean Median Mode
SD Calculator
SD Calculator
Quartiles & IQR
Quartiles & IQR
Frequency Table
Frequency Table
Correlation (r)
Correlation (r)
Normal Probability
Normal Probability
Z-Score Calculator
Z-Score Calculator
Confidence Interval
Confidence Interval
Sample Size
Sample Size
Mark & Recapture
Mark & Recapture
P-Value Calculator
P-Value Calculator
Percentage and ratio calculators
Percentage Calc
Percentage Calc
Percent Change
Percent Change
Percent Difference
Percent Difference
Percent Error
Percent Error
Ratio Calculator
Ratio Calculator
Discount Calculator
Discount Calculator
Sales Tax Calculator
Sales Tax Calculator
Margin Calculator
Margin Calculator
Speed calculators
Speed Calculator
Speed Calculator
Density and concentration calculators
Density
Density
Molarity
Molarity
Molar Mass
Molar Mass
Physics and electricity calculators
Ohm's Law
Ohm's Law
Watts to Amps
Watts to Amps
Resistor Colors
Resistor Colors
Voltage Drop
Voltage Drop
Unit conversion calculators
Weight Converter
Weight Converter
Shoe Size Converter
Shoe Size Converter
Integer and signed number calculators
Long Division
Long Division
LCM Calculator
LCM Calculator
GCF Calculator
GCF Calculator
Integer Calculator
Integer Calculator
Prime Factorization
Prime Factorization
Diophantine Solver
Diophantine Solver
Modulo Calculator
Modulo Calculator
Factor Calculator
Factor Calculator
Roman Numerals
Roman Numerals
Fraction, decimal and rounding calculators
Fraction Calculator
Fraction Calculator
Mixed Numbers
Mixed Numbers
Simplify Fractions
Simplify Fractions
Fraction to Decimal
Fraction to Decimal
Decimal to Fraction
Decimal to Fraction
Rounding
Rounding
Equation and inequality calculators
Linear Equation
Linear Equation
Linear Systems
Linear Systems
Quadratic Formula
Quadratic Formula
Absolute Value
Absolute Value
Quadratic Inequality
Quadratic Inequality
Polynomial calculators
Binomial Theorem
Binomial Theorem
Square root and nth root calculators
Simplify Radicals
Simplify Radicals
Nth Root
Nth Root
Exponent and logarithm calculators
Exponents
Exponents
Log Calculator
Log Calculator
Number of Digits
Number of Digits
Scientific Notation
Scientific Notation
Sci. Notation Math
Sci. Notation Math
Half-Life
Half-Life
Complex number calculators
Complex Numbers
Complex Numbers
Polar Form
Polar Form
De Moivre
De Moivre
Function and graph calculators
Slope Calculator
Slope Calculator
Linear Function
Linear Function
Direct & Inverse Variation
Direct & Inverse Variation
y = ax² Calculator
y = ax² Calculator
Distance Formula
Distance Formula
3D Distance
3D Distance
Section Formula
Section Formula
Point to Line
Point to Line
Lat/Long Distance
Lat/Long Distance
Complete the Square
Complete the Square
Circle Equation
Circle Equation
Conic Sections
Conic Sections
Polar Coordinates
Polar Coordinates
Sequence calculators
Arithmetic Sequence
Arithmetic Sequence
Geometric Sequence
Geometric Sequence
Fibonacci Sequence
Fibonacci Sequence
Recurrence Relation
Recurrence Relation
Vector calculators
Vector Calculator
Vector Calculator
Cross Product
Cross Product
Matrix calculators
Matrix Calculator
Matrix Calculator
Determinant
Determinant
Inverse Matrix
Inverse Matrix
Plane geometry calculators
Sin Cos Tan
Sin Cos Tan
Degrees ⇔ Radians
Degrees ⇔ Radians
a sin θ + b cos θ
a sin θ + b cos θ
Triangle Solver
Triangle Solver
Triangle Area
Triangle Area
Right Triangle
Right Triangle
Pythagorean Theorem
Pythagorean Theorem
Polygon Angles
Polygon Angles
Scale Factor
Scale Factor
Parallel Lines
Parallel Lines
Rectangle Area
Rectangle Area
Parallelogram Area
Parallelogram Area
Trapezoid Area
Trapezoid Area
Circle Calculator
Circle Calculator
Sector Area
Sector Area
Inscribed Angle
Inscribed Angle
Ellipse Area
Ellipse Area
Solid geometry calculators
Cube Volume
Cube Volume
Cube Surface Area
Cube Surface Area
Box Volume
Box Volume
Box Surface Area
Box Surface Area
Cylinder Volume
Cylinder Volume
Cylinder Surface
Cylinder Surface
Sphere Volume
Sphere Volume
Sphere Surface
Sphere Surface
Spherical Cap Volume
Spherical Cap Volume
Cap Surface Area
Cap Surface Area
Ellipsoid Volume
Ellipsoid Volume
Ellipsoid Surface
Ellipsoid Surface
Pyramid Volume
Pyramid Volume
Pyramid Surface
Pyramid Surface
Cone Volume
Cone Volume
Cone Surface Area
Cone Surface Area
Frustum Volume
Frustum Volume
Frustum Surface Area
Frustum Surface Area
Pipe Volume
Pipe Volume
Capsule Volume
Capsule Volume
Capsule Surface Area
Capsule Surface Area
Date and time calculators
Age Calculator
Age Calculator
Days Between Dates
Days Between Dates
Date Calculator
Date Calculator
Hours From Now
Hours From Now
Day of the Week
Day of the Week
Time Calculator
Time Calculator
Time Zone Converter
Time Zone Converter
Hours Calculator
Hours Calculator
Time Duration
Time Duration
Time Card
Time Card
Finance and economics calculators
Compound Interest
Compound Interest
Simple Interest
Simple Interest
Interest Calculator
Interest Calculator
TVM Calculator
TVM Calculator
Present Value
Present Value
Future Value
Future Value
ROI Calculator
ROI Calculator
IRR Calculator
IRR Calculator
Payback Period
Payback Period
Average Return
Average Return
GDP Calculator
GDP Calculator
Web marketing and ad metric calculators
CTR Calculator
CTR Calculator
Conversion Rate
Conversion Rate
CPC, CPM & CPA
CPC, CPM & CPA
ROAS Calculator
ROAS Calculator
Break-Even CPA
Break-Even CPA
LTV Calculator
LTV Calculator
CAC Calculator
CAC Calculator
Churn Rate
Churn Rate
A/B Test Calc
A/B Test Calc
A/B Sample Size
A/B Sample Size
SEO Traffic
SEO Traffic
Break-Even Point
Break-Even Point
Markup vs. Margin
Markup vs. Margin
CAGR Calculator
CAGR Calculator
Health and fitness calculators
BMI Calculator
BMI Calculator
Sleep Calculator
Sleep Calculator
Calorie Calculator
Calorie Calculator
BMR Calculator
BMR Calculator
TDEE Calculator
TDEE Calculator
Ideal Weight
Ideal Weight
Body Fat Calculator
Body Fat Calculator
Lean Body Mass
Lean Body Mass
Calories Burned
Calories Burned
Protein Intake
Protein Intake
Macro Calculator
Macro Calculator
Carb Calculator
Carb Calculator
Fat Intake
Fat Intake
Child Height
Child Height
Sports calculators
Golf Handicap
Golf Handicap
Pace Calculator
Pace Calculator
1RM Calculator
1RM Calculator
Target Heart Rate
Target Heart Rate
Weather calculators
Heat Index
Heat Index
Wind Chill
Wind Chill
Dew Point
Dew Point
Computer calculators
Base Converter
Base Converter
Subnet Calculator
Subnet Calculator
Download Time
Download Time
Household energy and budget calculators
Electricity Cost
Electricity Cost
kWh to Cost
kWh to Cost
Yearly kWh to Cost
Yearly kWh to Cost
AC Size (BTU)
AC Size (BTU)
AC Running Cost
AC Running Cost
Heating Costs
Heating Costs
Gas vs Electric
Gas vs Electric
LED Savings
LED Savings
Salary Calculator
Salary Calculator
Budget Calculator
Budget Calculator
Car calculators
Trip Gas Cost
Trip Gas Cost
EV Charging Cost
EV Charging Cost
EV vs Gas Cost
EV vs Gas Cost
MPG Calculator
MPG Calculator
Tire Size
Tire Size
Solar power and battery calculators
Solar Output
Solar Output
Solar Panel Count
Solar Panel Count
Solar Payback
Solar Payback
Battery Size
Battery Size
Home and DIY calculators
Tile Calculator
Tile Calculator
Stair Calculator
Stair Calculator
Concrete Volume
Concrete Volume
Wall Area
Wall Area
Wallpaper Rolls
Wallpaper Rolls
Paint Calculator
Paint Calculator
Flooring Needed
Flooring Needed
Exterior Walls
Exterior Walls
Gravel Needed
Gravel Needed
Mortar Mix
Mortar Mix
Slope Grade
Slope Grade
Lumber Cut List
Lumber Cut List
Lot Coverage/FAR
Lot Coverage/FAR
Sheet Vinyl Roll
Sheet Vinyl Roll
Insulation Needed
Insulation Needed
Curtain Size
Curtain Size
TV Size & Distance
TV Size & Distance
Soil Needed
Soil Needed
Sod Needed
Sod Needed
Block Calculator
Block Calculator
Brick Calculator
Brick Calculator
Deck Materials
Deck Materials
Ramp Length
Ramp Length
Pilot Hole Size
Pilot Hole Size
Room Ventilation
Room Ventilation
Paint Thinning
Paint Thinning
Baseboard & Trim
Baseboard & Trim
Blind Size
Blind Size
Picture Hanging
Picture Hanging
Drain Slope
Drain Slope
Screw Calculator
Screw Calculator
Board Feet
Board Feet
Fence Calculator
Fence Calculator
Wood Shrinkage
Wood Shrinkage
Caulk Calculator
Caulk Calculator
Heat Loss
Heat Loss
Furniture Fit
Furniture Fit
Moving Boxes
Moving Boxes
Storage Capacity
Storage Capacity
Plywood Cuts
Plywood Cuts
Shelf Sag
Shelf Sag

Customer Acquisition Cost (CAC) Calculator with LTV:CAC Ratio and Payback Period

First, under "Type of calculation", choose whether to calculate CAC, work back from a budget and target CAC to the customers you need, or work back from LTV and a target LTV:CAC ratio to the max CAC. To calculate CAC, the cost breakdown (ad spend, staff, tools) and new customers are required; LTV, monthly ARPU and gross margin are optional. Depending on what you fill in, it also calculates the paid CAC, LTV:CAC ratio and CAC payback period, and graphs cumulative gross profit against CAC.

Enter amounts as plain numbers in dollars. For % fields, enter just the number (for 40%, enter "40"). Enter costs and new customers for the same period (for example, the same month or the same quarter). If you do not know the cost breakdown, put the total in the ad spend field and it still works.
Result and graph
Choose the type of calculation on the left, enter the values and press "Calculate". The result and a graph of cumulative gross profit against CAC (the payback period) will appear here.

What you can do on this page

  • Calculates customer acquisition cost (CAC) as "total sales and marketing cost (ad spend + staff + tools, creative and so on) ÷ new customers". It also gives the paid CAC: ad spend alone divided by the customers who came from ads
  • Enter the LTV (customer lifetime value) to get the LTV:CAC ratio, how many times CAC the LTV is
  • Enter monthly ARPU (monthly revenue per customer) and gross margin to get the number of months to earn back CAC (the CAC payback period), with a graph showing where cumulative gross profit meets CAC
  • It also works backward: "the new customers you need from a budget and a target CAC" and "the most you can spend to win one customer (max CAC) from LTV and a target LTV:CAC ratio"
  • A plain-language explanation of the formulas and copy-and-paste formulas for Excel, Google Sheets and Python are all on this page
On this page, CAC is the blended CAC, which adds up all sales and marketing costs, not just ad spend, and divides by all new customers won in the same period (from every channel). The paid CAC, ad spend divided by new customers from ads, is calculated in a separate field. The CAC payback period is "CAC ÷ monthly gross profit per customer", a simple definition that ignores customers who cancel before payback. To find the LTV itself, use the customer lifetime value (LTV) calculator page.

What is this calculation used for?

Deciding whether to spend more or less on ads (online advertising and marketing)

With $30,000 in ad spend and 25 new customers from ads, the paid CAC is \(30000 \div 25 = 1200\) dollars. If the gross profit LTV of one customer is $3,000, the LTV:CAC ratio is \(3000 \div 1200 = 2.5\), so each customer you win still adds gross profit. But if your company aims for about 3x, it helps you decide whether to improve ad efficiency or grow LTV first.
Compare with the gross profit LTV, not the revenue LTV. With revenue, the numbers look like they work out before the cost of goods is even paid.

Seeing the efficiency of the whole business, including customers who come for free (management and business planning)

Divide the same month's total cost of $50,000 by all 50 new customers, including those from referrals and search, and the blended CAC is \(50000 \div 50 = 1000\) dollars. It is smaller than the paid CAC of $1,200 because customers from other channels (word of mouth, search, referrals) spread the cost thinner.
Use the blended CAC to see "how much we spend per customer to grow" for the whole business, and the paid CAC to decide how to split the ad budget. If you look only at the blended CAC, it is easy to miss falling ad efficiency, so track both side by side.

Planning cash flow by seeing how many months acquisition spending takes to come back (SaaS and subscriptions)

With a CAC of $1,000, a $250 monthly price and a 40% gross margin, the monthly gross profit per customer is \(250 \times 40 \div 100 = 100\) dollars, and the CAC payback period is \(1000 \div 100 = 10\) months. For those 10 months you are still earning back acquisition money you paid up front, so you need cash to cover that time.
If you win 100 customers a month, you pay $100,000 up front every month and it comes back over 10 months, so the balance waiting to be earned back grows to around $500,000 at most. The longer the payback period, the bigger this up-front amount. Even with a good LTV:CAC ratio, a business with a long payback period needs more cash on hand.

Setting a customer goal from next month's budget (marketing and sales targets)

If next month's sales and marketing budget is $60,000 and you want to keep CAC within $800, you need \(60000 \div 800 = 75\) new customers. With 74 or fewer, CAC goes above $800. "At least 75 customers if we spend the whole budget" becomes the team's goal.
If instead the goal is set first at "50 customers", the budget you can use is up to \(800 \times 50 = 40000\) dollars. Once you know this multiplication and division, you can start from either the budget or the customer goal and get the other right away.

Setting a ceiling per customer for a new business or channel (new ventures and e-commerce)

If the gross profit LTV is $3,000 and you want an LTV:CAC ratio of at least 3x, the max CAC is \(3000 \div 3 = 1000\) dollars. When you try a new ad platform or a trade show, you can draw the line: "stop if it costs more than $1,000 per customer".
LTV is a forecast, so if the lifetime or churn assumptions are optimistic, the max CAC will be too. Working out the max CAC with somewhat strict assumptions (for example, a shorter lifetime) protects you if actual acquisition costs swing.

Formulas and figures

Formula for customer acquisition cost (blended CAC)
Figure
Standard notation (the usual math form)
\(\mathrm{CAC}\) \(=\) \(E\) \(\div\) \(N\)
In words (symbols replaced with words)
③ \(\mathrm{CAC}\): customer acquisition cost \(=\) ① \(E\): total sales and marketing cost \(\div\) ② \(N\): new customers
The formula in words
① Take the \(E\): total sales and marketing cost (ad spend + staff + tools, creative and so on),
② divide it by the \(N\): new customers , and you get the
③ \(\mathrm{CAC}\): customer acquisition cost
Quick example
If in one month you spend $30,000 on ads, $15,000 on sales and marketing staff and $5,000 on tools and creative, and win 50 new customers (from all channels), the CAC is
customer acquisition cost \(\mathrm{CAC}\) \(=\) total cost ($50,000) \(\div\) new customers (50)
\(30000 + 15000 + 5000 = 50000\)
\(50000 \div 50 = 1000\)
Key idea
CAC (customer acquisition cost) is "how much it cost, on average, to win one new customer". The cost on top includes everything spent on winning new customers: not only ad spend but also the cost of sales and marketing staff, software subscriptions, landing page and banner design, agency fees and so on. The bottom is the number of new customers won in the same period, counting everyone, not only those from ads but also those from referrals, search and word of mouth. The value found this way is called the blended CAC, and when this page says just "CAC", it refers to this. Always use the same period for the top and bottom (a month of costs with a month of new customers). Do not include costs aimed at existing customers (support and retention programs). The difference from CPA (ad spend per conversion), a similar metric, is explained after the paid CAC formula.
Formula for the paid CAC (from ad spend and customers from ads)
Standard notation (the usual math form)
\(\mathrm{CAC_{ad}}\) \(=\) \(E_{ad}\) \(\div\) \(N_{ad}\)
In words (symbols replaced with words)
③ \(\mathrm{CAC_{ad}}\): paid CAC \(=\) ① \(E_{ad}\): ad spend \(\div\) ② \(N_{ad}\): new customers from ads
The formula in words
① Take only the \(E_{ad}\): ad spend ,
② divide it by the \(N_{ad}\): new customers from ads , and you get the
③ \(\mathrm{CAC_{ad}}\): paid CAC
Quick example
With $30,000 in ad spend, if 25 of the 50 new customers came from ads, the paid CAC is
paid CAC \(\mathrm{CAC_{ad}}\) \(=\) ad spend ($30,000) \(\div\) new customers from ads (25)
\(30000 \div 25 = 1200\)
Key idea
With the same month's numbers, the blended CAC is $1,000 and the paid CAC is $1,200. The paid CAC looks only at customers who would stop coming if you stopped the ads, and shows the cost per customer from ads. It is used to decide whether to spend more or less on ads. The blended CAC also counts customers who came for free (referrals, search), so it is usually smaller than the paid CAC (but its top also includes staff and tool costs, so if those are large, the blended CAC can be higher). "Our CAC is $1,000" says different things depending on the definition, so match the definitions before comparing. The "CPA" in an ads dashboard is ad spend divided by the number of conversions (purchases, sign-ups, quote requests and so on). The differences from CAC are that one conversion is not always one customer (some people request a quote but never sign), and that the top is only ad spend. To work with CPA, use the CPC, CPM and CPA calculator or the break-even CPA calculator page.
Formula for the LTV:CAC ratio
Standard notation (the usual math form)
\(R\) \(=\) \(\mathrm{LTV}\) \(\div\) \(\mathrm{CAC}\)
In words (symbols replaced with words)
③ \(R\): LTV:CAC ratio (x) \(=\) ① \(\mathrm{LTV}\): customer lifetime value \(\div\) ② \(\mathrm{CAC}\): customer acquisition cost
The formula in words
① Take the \(\mathrm{LTV}\): customer lifetime value
② divide it by the \(\mathrm{CAC}\): customer acquisition cost , and you get the
③ \(R\): LTV:CAC ratio (x)
Quick example
If the gross profit LTV of one customer is $3,000 and the CAC is $1,000, the LTV:CAC ratio is
LTV:CAC ratio \(R\) \(=\) LTV ($3,000) \(\div\) CAC ($1,000)
\(3000 \div 1000 = 3\)
Key idea
The LTV:CAC ratio is "how many times the cost of winning a customer is the value that customer brings". At 1x you break even; below 1x, every customer you win loses money. In SaaS and subscriptions, "about 3x" (often written 3:1) is a common benchmark, but it is a rule of thumb, not a rule. The right ratio depends on how high your gross margin is, how much cash you have, and how many years customers stay. Two cautions when comparing. First, use the LTV on a gross profit basis (after the cost of goods), not on a revenue basis; a revenue LTV makes the ratio look larger than it is. Second, LTV is a forecast while CAC is money already spent, so if the LTV assumptions (lifetime or churn rate) are optimistic, so is the ratio. Even with the same ratio, if the CAC payback period below is long, watch your cash flow during that time.
Formula for the CAC payback period
Figure
Standard notation (the usual math form)
\(T\) \(=\) \(\mathrm{CAC}\) \(\div\) \(g\)
In words (symbols replaced with words)
③ \(T\): CAC payback period (months) \(=\) ① \(\mathrm{CAC}\): customer acquisition cost \(\div\) ② \(g\): monthly gross profit per customer
The formula in words
① Take the \(\mathrm{CAC}\): customer acquisition cost
② divide it by the \(g\): monthly gross profit per customer (= monthly ARPU × gross margin ÷ 100), and you get the
③ \(T\): CAC payback period (months)
Quick example
With a CAC of $1,000, monthly revenue per customer (monthly ARPU) of $250 and a gross margin of 40%, the CAC payback period is
CAC payback period \(T\) (months) \(=\) CAC ($1,000) \(\div\) monthly gross profit ($250 × 40% = $100)
\(250 \times 40 \div 100 = 100\)
\(1000 \div 100 = 10\)
Key idea
The CAC payback period is "how many months of the gross profit a customer brings each month it takes to earn back what you spent to win them". As the figure shows, it is the month when the line of cumulative gross profit, stacked up month by month, reaches the height of CAC. The standard is to divide by monthly gross profit (monthly ARPU × gross margin). Dividing by revenue without the gross margin makes payback look faster by the amount of the cost of goods (when the gross margin is blank, this calculator shows in the result that it used a revenue basis). This is a simple definition that assumes "no one cancels before payback" and "monthly gross profit stays the same". In reality some customers cancel along the way, so if the payback period is longer than the average lifetime in months (100 ÷ monthly churn rate (%); at 5% monthly churn, \(100 \div 5 = 20\) months), the average customer never pays back. The shorter the payback, the sooner the money spent on acquisition comes back to fund the next customers, so for cash flow it is as important as the LTV:CAC ratio. For the payback of investments such as equipment, see the payback period calculator page.
Formula for the new customers needed (from a budget and target CAC)
Standard notation (the usual math form)
\(N\) \(=\) \(B\) \(\div\) \(\mathrm{CAC_{t}}\)
In words (symbols replaced with words)
③ \(N\): new customers needed \(=\) ① \(B\): budget \(\div\) ② \(\mathrm{CAC_{t}}\): target CAC
The formula in words
① Take the \(B\): budget
② divide it by the \(\mathrm{CAC_{t}}\): target CAC , and you get the
③ \(N\): new customers needed (round up if it does not divide evenly)
Quick example
If next month's sales and marketing budget is $60,000 and you want to keep CAC within $800, the new customers you need are
new customers needed \(N\) \(=\) budget ($60,000) \(\div\) target CAC ($800)
\(60000 \div 800 = 75\)
Key idea
This is the first formula, \(\mathrm{CAC} = E \div N\), rearranged to solve for the number of customers \(N\). Assuming you spend the whole budget, it is the floor: "if you win fewer customers than this, CAC goes over the target". If it does not divide evenly, round up (for example, \(60000 \div 700 \approx 85.7\) calls for 86 customers; with 85, CAC is \(60000 \div 85 \approx 706\) dollars, over the target). If instead the customer goal comes first and you want to know how much budget you can use, it is \(B = \mathrm{CAC_{t}} \times N\) (for example, 50 customers × $800 = up to $40,000). The calculator on this page solves for the number of customers, but the multiplication gives the budget right away.
Formula for the max CAC (from LTV and a target LTV:CAC ratio)
Standard notation (the usual math form)
\(\mathrm{CAC_{max}}\) \(=\) \(\mathrm{LTV}\) \(\div\) \(R_{t}\)
In words (symbols replaced with words)
③ \(\mathrm{CAC_{max}}\): max CAC \(=\) ① \(\mathrm{LTV}\): customer lifetime value \(\div\) ② \(R_{t}\): target LTV:CAC ratio (x)
The formula in words
① Take the \(\mathrm{LTV}\): customer lifetime value
② divide it by the \(R_{t}\): target LTV:CAC ratio (x) , and you get the
③ \(\mathrm{CAC_{max}}\): max CAC
Quick example
If the gross profit LTV is $3,000 and you want an LTV:CAC ratio of at least 3x, the max CAC (the most you can spend to win one customer) is
max CAC \(\mathrm{CAC_{max}}\) \(=\) LTV ($3,000) \(\div\) target LTV:CAC ratio (3x)
\(3000 \div 3 = 1000\)
Key idea
This is the third formula, \(R = \mathrm{LTV} \div \mathrm{CAC}\), rearranged to solve for CAC. It is the ceiling: "you can spend up to one third of LTV to win one customer". The answer, $1,000, is the dividing line: "with a CAC of exactly $1,000, you just reach the 3x target", so in practice keep CAC below it. With a target ratio of 1x, the max CAC equals the LTV itself (acquisition cost and lifetime gross profit break even). Once the max CAC is set, budget ÷ max CAC tells you "the minimum number of customers to win with that budget" (this calculator does it at the same time if you enter a budget). To set a ceiling on ad spend per conversion (target CPA) from order value and gross margin, use the break-even CPA calculator page.
CAC is "total sales and marketing cost ÷ new customers"; ad spend alone divided by customers from ads is kept separate as the paid CAC. Divide LTV by CAC for the LTV:CAC ratio, and divide CAC by the monthly gross profit per customer for the CAC payback period (in months). Rearrange the formulas, and you can work back from a budget and target CAC to the customers you need, or from LTV and a target ratio to the max CAC.

Symbols and terms

Symbols

\(\mathrm{CAC}\) C-A-C (or "cack") Customer acquisition cost. The average cost of winning one new customer. On this page it is the blended CAC: total cost divided by all new customers.
\(E\) ee Total sales and marketing cost, from the first letter of "expense". Everything spent on winning new customers added up: ad spend, staff, tools, creative and so on.
\(N\) en New customers, from the first letter of "number". The customers who signed up or bought for the first time in the same period as the costs, counting everyone, whether from ads or not. In the reverse formula, it is the number of customers needed.
\(\mathrm{CAC_{ad}}\) C-A-C sub ad Paid CAC. The subscript ad is short for "advertising", added on this page to tell it apart. Ad spend \(E_{ad}\) divided by new customers from ads \(N_{ad}\).
\(E_{ad}\) E sub ad Ad spend. Only the part of the cost \(E\) that went to running ads.
\(N_{ad}\) N sub ad New customers from ads. How many of the new customers \(N\) came by clicking an ad.
\(\mathrm{LTV}\) L-T-V Customer lifetime value. The total value one customer brings while they stay with you. To compare with CAC, the standard is to use the LTV on a gross profit basis (after the cost of goods).
\(R\) ar LTV:CAC ratio, from the first letter of "ratio". How many times CAC the LTV is. \(R_{t}\), with a subscript, is the target ratio.
\(T\) tee CAC payback period (months), from the first letter of "time". The number of months of gross profit it takes to earn back the cost of winning a customer.
\(g\) gee Monthly gross profit per customer, from the first letter of "gross profit". Monthly ARPU times the gross margin, divided by 100. Without a gross margin, it is the monthly ARPU itself (revenue basis).
\(B\) bee Budget, from the first letter of "budget". The total sales and marketing cost you plan to spend in the period.
\(\mathrm{CAC_{t}}\) C-A-C sub t Target CAC. The subscript t is the first letter of "target": the most you have decided to spend to win one customer.
\(\mathrm{CAC_{max}}\) C-A-C sub max Max CAC. The subscript max is short for "maximum": the most you can spend to win one customer, found by dividing LTV by the target ratio.

Terms

customer acquisition cost (CAC) The average cost of winning one new customer. Divide total sales and marketing cost by the new customers in the same period. It is like the price you paid to bring in one customer; comparing it with LTV (the value one customer brings) tells you whether the acquisition cost is worth it.
blended CAC CAC with total cost divided by all new customers (including those from referrals, search and word of mouth). Because some customers come for free, it is usually smaller than the paid CAC. Used to see the efficiency of the whole business.
paid CAC CAC with only ad spend divided by new customers from ads. Because it leaves out customers who come for free, it is usually larger than the blended CAC. Used to decide how much to spend on ads.
CPA (cost per acquisition) Short for cost per acquisition (or cost per action). Ad spend divided by the number of conversions (purchases, sign-ups, quote requests and so on), shown in ads dashboards. It differs from CAC in two ways - the top is only ad spend, and the bottom is the number of conversions, which is not always the number of customers (some people request a quote but never sign).
LTV:CAC ratio LTV divided by CAC, the best-known measure of profit per customer. Looking at profit per customer (per unit) this way is called unit economics. Below 1x, every customer you win loses money. About 3x is a common SaaS benchmark, but the right value depends on the industry and how much cash you have.
CAC payback period The number of months it takes for the gross profit a customer brings each month to earn back what you spent to win them (CAC). Found with CAC ÷ monthly gross profit per customer. The shorter it is, the sooner the money comes back to fund the next customers. It is a simple definition that ignores cancellations before payback, so if it is longer than the average lifetime, the average customer never pays back.
monthly ARPU Short for average revenue per user. The average revenue from one customer per month, found with "that month's revenue ÷ that month's customers". For the payback period, multiply it by the gross margin to get the monthly gross profit first.
gross margin Gross profit (revenue − cost of goods) as a percentage of revenue. If $250 of revenue has $150 of cost of goods, the gross profit is $100 and the gross margin is 40%. See the profit margin calculator page for details.
customer lifetime value (LTV) The total value one customer brings from their first purchase until they leave. For a store it is "order value × purchase frequency × lifespan"; for a subscription it is "ARPU × gross margin ÷ churn rate". To compare with CAC, use the gross profit basis. See the customer lifetime value (LTV) calculator page for how to find it.
rounding up When a value has a decimal part, moving it up to the next whole number. If the customers needed come out uneven, such as \(85.7\), 85 customers would put CAC over the target, so round up to 86.

Good to know before you start

Here is what helps you use the calculation on this page with real understanding, not just by pressing the button.

Percents (Grades 6–7)
  • Knowing that a percent is found as "part ÷ whole"
  • Being able to switch between percentages and decimals (\(40\% = 0.4\))
  • Being able to find a percentage of an amount by multiplication, as in "40% of revenue" (\(250 \times 0.4 = 100\))
Unit rates and averages (Grade 6)
  • Knowing that an amount "per customer" is total ÷ number of customers (total cost ÷ new customers = cost per customer)
  • Knowing that "how many times" is found by dividing one amount by the other (LTV ÷ CAC)
Division and rounding up (Grades 4–5)
  • Being able to round an uneven division up or down depending on the purpose (the customers needed are rounded up)
Variables and rearranging equations (Grades 7–8)
  • Understanding a formula with letters such as \(\mathrm{CAC} = E \div N\), and being able to rearrange it to find another quantity, as in \(N = E \div \mathrm{CAC}\)
Graphs of proportional relationships (Grade 7)
  • Knowing that cumulative gross profit that grows by the same amount every month is a straight line through the origin (a proportional relationship), and reading the payback period as the month when that line reaches the height of CAC

How to calculate it in Excel

Copy the whole table below and paste it into cell A1 in Excel. It works as is.
Table to find customer acquisition cost (blended CAC)
Ad spend ($) 30000
Sales and marketing staff ($) 15000
Tools, creative and other ($) 5000
New customers N 50
Total cost E ($) =B1+B2+B3
CAC (blended, $) =B5/B4
Table to find the paid CAC
Ad spend Ead ($) 30000
New customers from ads Nad 25
Paid CAC ($) =B1/B2
Table to find the LTV:CAC ratio
LTV (gross profit basis, $) 3000
CAC ($) 1000
LTV:CAC ratio (x) =B1/B2
Table to find the CAC payback period
CAC ($) 1000
Monthly ARPU A ($) 250
Gross margin M (%) 40
Monthly gross profit per customer g ($) =B2*B3/100
CAC payback period T (months) =B1/B4
Table to find the new customers needed (from a budget and target CAC)
Budget B ($) 60000
Target CAC ($) 800
New customers needed (exact) =B1/B2
New customers needed (rounded up) =ROUNDUP(B1/B2,0)
Table to find the max CAC (from LTV and a target LTV:CAC ratio)
LTV (gross profit basis, $) 3000
Target LTV:CAC ratio Rt (x) 3
Max CAC ($) =B1/B2
After pasting, the upper rows of column B are your inputs and the lower rows are calculated automatically.
For example, in the first table B5 shows 50000 (total cost) and B6 shows 1000 (CAC $1,000); B3 of the second shows 1200; B3 of the third shows 3 (3x); in the fourth B4 shows 100 and B5 shows 10 (10 months); B3 and B4 of the fifth show 75 (75 customers); and B3 of the sixth shows 1000 (max CAC $1,000).
ROUNDUP in the fifth table is a function that rounds up the decimal part, turning an uneven result such as 85.7 customers into 86. Just replace the inputs with your own numbers.

How to calculate it in Google Sheets

Copy the whole table below and paste it into cell A1 in Google Sheets. It works as is.
Table to find customer acquisition cost (blended CAC)
Ad spend ($) 30000
Sales and marketing staff ($) 15000
Tools, creative and other ($) 5000
New customers N 50
Total cost E ($) =B1+B2+B3
CAC (blended, $) =B5/B4
Table to find the paid CAC
Ad spend Ead ($) 30000
New customers from ads Nad 25
Paid CAC ($) =B1/B2
Table to find the LTV:CAC ratio
LTV (gross profit basis, $) 3000
CAC ($) 1000
LTV:CAC ratio (x) =B1/B2
Table to find the CAC payback period
CAC ($) 1000
Monthly ARPU A ($) 250
Gross margin M (%) 40
Monthly gross profit per customer g ($) =B2*B3/100
CAC payback period T (months) =B1/B4
Table to find the new customers needed (from a budget and target CAC)
Budget B ($) 60000
Target CAC ($) 800
New customers needed (exact) =B1/B2
New customers needed (rounded up) =ROUNDUP(B1/B2,0)
Table to find the max CAC (from LTV and a target LTV:CAC ratio)
LTV (gross profit basis, $) 3000
Target LTV:CAC ratio Rt (x) 3
Max CAC ($) =B1/B2
The same formulas as in Excel (including ROUNDUP) work as is. Copy the whole table, paste it into cell A1, and replace the inputs with your own numbers.

How to calculate it in Python

import math

# CAC (blended CAC): total cost ÷ new customers
ad_cost = 30000         # ad spend ($)
labor_cost = 15000      # sales and marketing staff ($)
tool_cost = 5000        # tools, creative and other ($)
new_customers = 50      # new customers (from all channels)

total_cost = ad_cost + labor_cost + tool_cost
cac = total_cost / new_customers
print(f"Total cost: ${total_cost}")
print(f"CAC (blended CAC): ${cac}")

# Paid CAC: ad spend ÷ new customers from ads
ad_customers = 25
paid_cac = ad_cost / ad_customers
print(f"Paid CAC: ${paid_cac}")

# LTV:CAC ratio: LTV (gross profit basis) ÷ CAC
ltv = 3000
ltv_cac_ratio = ltv / cac
print(f"LTV:CAC ratio: {ltv_cac_ratio}x")

# CAC payback period: CAC ÷ monthly gross profit (= monthly ARPU × gross margin ÷ 100)
arpu = 250              # monthly ARPU ($)
gross_margin = 40       # gross margin (%)
monthly_gross = arpu * gross_margin / 100
payback_months = cac / monthly_gross
print(f"Monthly gross profit per customer: ${monthly_gross}")
print(f"CAC payback period: {payback_months} months")

# Work back: new customers needed from a budget and target CAC (rounded up)
budget = 60000
target_cac = 800
required_customers = math.ceil(budget / target_cac)
print(f"New customers needed: {required_customers}")

# Work back: max CAC from LTV and a target LTV:CAC ratio
target_ratio = 3
max_cac = ltv / target_ratio
print(f"Max CAC: ${max_cac}")
Runs with the standard library only. In this example, the total cost is $50000, the CAC is $1000.0, the paid CAC is $1200.0, the LTV:CAC ratio is 3.0x, the monthly gross profit is $100.0, the CAC payback period is 10.0 months, the new customers needed are 75, and the max CAC is $1000.0. math.ceil is a function that rounds up the decimal part. Change the costs, customers, LTV and so on at the top and run it.

How to write it in LaTeX and other math languages (copy and paste)

Formula for customer acquisition cost (blended CAC)
CAC = E ÷ N
\mathrm{CAC} = \dfrac{E}{N}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>CAC</mi>
    <mo>=</mo>
    <mfrac><mi>E</mi><mi>N</mi></mfrac>
  </mrow>
</math>
CAC = E/N
expense/newCustomers
CAC := E/N;
CAC = E/N;
CAC = E/N
Formula for the paid CAC (from ad spend and customers from ads)
CACad = Ead ÷ Nad
\mathrm{CAC_{ad}} = \dfrac{E_{ad}}{N_{ad}}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <msub><mi>CAC</mi><mi>ad</mi></msub>
    <mo>=</mo>
    <mfrac>
      <msub><mi>E</mi><mi>ad</mi></msub>
      <msub><mi>N</mi><mi>ad</mi></msub>
    </mfrac>
  </mrow>
</math>
CAC_(ad) = E_(ad)/N_(ad)
adCost/adCustomers
CACad := Ead/Nad;
CACad = Ead/Nad;
CAC_ad = E_ad/N_ad
Formula for the LTV:CAC ratio
R = LTV ÷ CAC
R = \dfrac{\mathrm{LTV}}{\mathrm{CAC}}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>R</mi>
    <mo>=</mo>
    <mfrac><mi>LTV</mi><mi>CAC</mi></mfrac>
  </mrow>
</math>
R = LTV/CAC
ltv/cac
R := LTV/CAC;
R = LTV/CAC;
R = LTV/CAC
Formula for the CAC payback period
T = CAC ÷ g
T = \dfrac{\mathrm{CAC}}{g}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>T</mi>
    <mo>=</mo>
    <mfrac><mi>CAC</mi><mi>g</mi></mfrac>
  </mrow>
</math>
T = CAC/g
cac/monthlyGross
T := CAC/g;
T = CAC/g;
T = CAC/g
Formula for the new customers needed (from a budget and target CAC)
N = B ÷ CACt
N = \dfrac{B}{\mathrm{CAC_{t}}}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>N</mi>
    <mo>=</mo>
    <mfrac>
      <mi>B</mi>
      <msub><mi>CAC</mi><mi>t</mi></msub>
    </mfrac>
  </mrow>
</math>
N = B/CAC_t
budget/targetCac
N := B/CACt;
N = B/CACt;
N = B/CAC_t
Formula for the max CAC (from LTV and a target LTV:CAC ratio)
CACmax = LTV ÷ Rt
\mathrm{CAC_{max}} = \dfrac{\mathrm{LTV}}{R_{t}}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <msub><mi>CAC</mi><mi>max</mi></msub>
    <mo>=</mo>
    <mfrac>
      <mi>LTV</mi>
      <msub><mi>R</mi><mi>t</mi></msub>
    </mfrac>
  </mrow>
</math>
CAC_(max) = LTV/R_t
ltv/targetRatio
CACmax := LTV/Rt;
CACmax = LTV/Rt;
CAC_max = LTV/R_t

How to have ChatGPT  do the calculation

You are a calculation assistant for marketing metrics. Do the following calculation by actually running Python code, and base your answer only on the numbers from the execution result (do not answer by mental math or guessing).

In one month, a company spent $30,000 on ads, $15,000 on sales and marketing staff and $5,000 on tools and creative, and won 50 new customers. 25 of them came from ads.
Find each of the following:
1. Blended CAC (total cost ÷ new customers)
2. Paid CAC (ad spend ÷ new customers from ads)
3. The LTV:CAC ratio when the gross profit LTV of one customer is $3,000 (LTV ÷ blended CAC)
4. The CAC payback period with a monthly ARPU of $250 and a 40% gross margin (blended CAC ÷ (monthly ARPU × gross margin ÷ 100))
5. The new customers needed if next month's budget is $60,000 and CAC must stay within $800 (budget ÷ target CAC, rounded up if it does not divide evenly)
6. The max CAC for an LTV:CAC ratio of at least 3x (LTV ÷ 3)

Show the formulas you used and the numbers from the execution result.

How to Use
  1. 1
    Enter your numbers
    Type the numbers you want to calculate with into the input fields
  2. 2
    Calculate
    Press the "Calculate" button
  3. 3
    Check the result
    The result appears on the spot. The same page also explains the idea behind the calculation and the formula
  DataChef Features
Easy and Free
Unlimited conversions for free.
No technical knowledge required.
Intuitive and user-friendly operation.
No Registration Required
Available immediately after access.
Can be used without registering personal information.
Safe and Secure
Fully SSL encrypted communication.
Automatic file deletion by clicking "download".
Fast
High-speed site access
and rapid file conversion.
No Watermark
No watermark.
No attribution required.
Commercial Use Available
Free for commercial use.
No need to contact us for commercial use permission.