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Protein Calculator (How Much Protein Do I Need per Day?)

Enter your age, sex, height, weight and activity level. Your daily protein needs are calculated with the US RDA and AMDR, and shown on one number line together with the reference values (the guide for people who exercise and the WHO safe level).

Enter height in cm and weight in kg. The results are estimates for healthy adults, not medical advice. If you have a condition that calls for adjusting protein (such as kidney disease), are pregnant or are still growing, talk with a doctor or a registered dietitian.
Result and graph
Enter your age, sex, height and weight in the fields on the left and press "Calculate". The result and a graph will appear here.

What you can do on this page

  • Enter your age, sex, height, weight and activity level, and you see on the spot how much protein you need per day (g/day)
  • It uses the two official US standards from the Dietary Reference Intakes (DRI): the RDA (0.8 g of protein per kg of body weight) and the AMDR (10–35% of your daily calories from protein)
  • For reference, it also shows a body-weight guide for people who exercise regularly (weight × 1.0–1.8 g/kg) and the safe level of the WHO (World Health Organization)
  • All the ranges are drawn as bands on one number line, so you can see your own range at a glance
  • The simple rule "body weight × factor (g/kg)" is explained with formulas and figures, so you can do the math yourself
  • A plain-language explanation of the formulas and copy-and-paste formulas for Excel, Google Sheets and Python are all on this page
All of these are estimates for healthy adults, not medical advice. If you have a condition that calls for limiting or adjusting protein, such as kidney disease, always follow the advice of your doctor or registered dietitian. If you are pregnant, breastfeeding or still growing, your needs are different, so check with a health professional first.

What is this calculation used for?

A starting point for a strength-training diet

When you want to build muscle, the usual first step is to set a protein goal with "body weight × factor (g/kg)" and then split the rest of your calories between fat and carbohydrate (this is the idea of counting macros). For example, a 150 lb (about 68 kg) person aiming for 1.6 g/kg needs about \(68 \times 1.6 \approx 109\) g a day.
Personal trainers and sports dietitians use formulas with the same "weight × g/kg" structure. If you change how often you train or what your goal is, you just choose a new factor. That is easy once you understand how the formula works.

Protecting muscle while losing weight

When you eat less to lose weight, cutting protein too is thought to make you lose muscle along with fat. Less muscle means a lower BMR, which can make it harder to lose weight and easier to regain it.
While dieting, first set a floor for protein: stay above the RDA (for example, about 46 g/day for a woman who weighs 126 lb) and the WHO safe level (weight × 0.83 g/kg), and get 1.0 g/kg or more if you exercise. Then build the rest of your meals around it. Using numbers this way helps you avoid risky diets.

Preventing undernutrition and frailty in older family members

As people age, they often eat less, and without anyone noticing, they can fall short on protein. This is known to lead to loss of muscle (sarcopenia) and a general decline of body and mind (frailty). Some expert groups suggest 1.0 to 1.2 g/kg a day for adults over 65, which is more than the RDA.
If you know the idea of "estimating a minimum from body weight × g/kg", you can notice unbalanced eating early, such as meals of just toast and coffee. Needs and kidney function differ a lot between older people, so talk with their doctor or a registered dietitian before changing their diet.

Reading Nutrition Facts labels against your own daily need

Nutrition Facts labels show how much protein a serving has, such as "Protein 20g", but without knowing your own daily need you cannot tell whether that is a lot. The Daily Value used for protein on labels is 50 g, which may not match your own need. If your need is 100 g/day, a snack with 20 g of protein is one-fifth of your day.
Many people eat most of their protein at dinner and little at breakfast. Just splitting your daily need across three meals can change what you choose to eat.

Used in nutrition care at hospitals and nursing homes

For patients in the hospital and people in long-term care, dietitians and doctors estimate protein needs with the same kind of formula as this page, "grams per kg of body weight". They raise the factor to help heal pressure ulcers (bedsores) or recover from surgery, and lower it when kidney function is reduced.
Adjusting the factor is truly the work of professionals. If you have a health condition, follow your doctor's or registered dietitian's advice on protein, not the estimates on this page.

Formulas and figures

AMDR range (US Dietary Reference Intakes, 10–35% of calories)
Figure
Standard notation (the usual math form)
\(P\) \(=\) \(r\) \(\times\) \(T\) \(\div\) \(4\)
In words (symbols replaced with words)
④ \(P\): daily protein range (g/day) \(=\) ② \(r\): share of calories from protein \(\times\) ① \(T\): total daily energy expenditure (kcal/day) \(\div\) ③ \(4\): energy per gram (kcal/g)
The formula in words
① Take the \(T\): total daily energy expenditure (TDEE, kcal/day)
② multiply it by the \(r\): share of calories from protein (0.10 to 0.35) to get the calories that come from protein
③ divide by the \(4\): energy in 1 g of protein (kcal/g)
④ and you get the \(P\): daily protein range (g/day)
Quick example
For a 30-year-old whose total daily energy expenditure (TDEE) is 2,400 kcal, getting 10–35% of it from protein means
\(P\): daily protein range \(=\) share (0.10 to 0.35) \(\times\) TDEE (2,400 kcal) \(\div\) per gram (4 kcal)
\(2400 \times 0.10 \div 4 = 60\)
\(2400 \times 0.35 \div 4 = 210\)
Key idea
The AMDR (Acceptable Macronutrient Distribution Range) is part of the US Dietary Reference Intakes. For adults 19 and older, it says that 10–35% of your daily calories can come from protein (10–30% for ages 4 to 18, so this calculator uses 10–30% at age 18). The idea is simple: the more calories you burn, the more protein you can eat while keeping a balanced diet. The range is set to lower the risk of chronic disease while still leaving room for enough of the other nutrients. One gram of protein has about 4 kcal (the Atwater factor, the same factor used for the calories on US Nutrition Facts labels). The DRI also sets an RDA (Recommended Dietary Allowance) of 0.8 g per kg of body weight for adults, which is the amount that covers the needs of almost all healthy people (see formula 3). This calculator shows both. The best target is an amount that is at least the RDA and also inside the AMDR range. For comparison, the Daily Value for protein on Nutrition Facts labels is 50 g, based on a 2,000-calorie diet.
Body-weight guide (reference: people who exercise)
Figure
Standard notation (the usual math form)
\(P\) \(=\) \(W\) \(\times\) \(c\)
In words (symbols replaced with words)
③ \(P\): daily protein guide (g/day) \(=\) ① \(W\): body weight (kg) \(\times\) ② \(c\): factor per kg of body weight (g/kg)
The formula in words
① Take the \(W\): body weight (kg)
② multiply it by the \(c\): factor per kg of body weight (1.0 to 1.8 g/kg if you exercise)
③ and you get the \(P\): daily protein guide (g/day)
Quick example
For a person who weighs 60 kg (about 132 lb) and exercises at least once a week (factor 1.0 to 1.8 g/kg), the guide is
\(P\): daily protein guide \(=\) weight (60 kg) \(\times\) factor (1.0 to 1.8 g/kg)
\(60 \times 1.0 = 60\)
\(60 \times 1.8 = 108\)
Key idea
"Body weight × factor (g/kg)" is the most basic way to estimate protein needs. A larger body has more muscle and organs, so it needs more protein. That is why protein is usually scaled to body weight. The range of 1.0 to 1.8 g/kg for people who exercise is a guide widely used in sports nutrition (exercise increases both the breakdown and the building of muscle, so you need more). Where you fall in the range depends on how hard you train and on your goal, such as building muscle. Sources differ a little; for example, a 2016 joint position statement for athletes (Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine) gives 1.2 to 2.0 g/kg. In the US, weight is usually in pounds. To use pounds, first divide by 2.2 to get kg, or use the factor per pound: 1.0 to 1.8 g/kg is about 0.45 to 0.82 g/lb. The RDA and the AMDR are meant for people with an ordinary lifestyle, so if you do serious strength or endurance training, use this body-weight guide as well.
RDA (US Recommended Dietary Allowance, 0.8 g/kg)
Figure
Standard notation (the usual math form)
\(P\) \(=\) \(W\) \(\times\) \(0.8\)
In words (symbols replaced with words)
③ \(P\): RDA (g/day) \(=\) ① \(W\): body weight (kg) \(\times\) ② \(0.8\): factor (g/kg)
The formula in words
① Take the \(W\): body weight (kg)
② multiply it by the \(0.8\): factor (g/kg)
③ and you get the \(P\): RDA (the amount that covers almost everyone, g/day)
Quick example
For a person who weighs 60 kg (about 132 lb), the RDA is
\(P\): RDA \(=\) weight (60 kg) \(\times\) factor (0.8 g/kg)
\(60 \times 0.8 = 48\)
Key idea
The RDA (Recommended Dietary Allowance) is the amount that meets the needs of about 97–98% of healthy people. For protein, it is 0.8 g per kg of body weight for adults 19 and older (0.85 g/kg for ages 14 to 18). In pounds, that is about 0.36 g per lb. For the reference adults used in the US tables, it works out to about 56 g/day for men and 46 g/day for women. The RDA is not an "ideal" amount. It is a baseline to avoid falling short. The WHO safe level of 0.83 g/kg, which this calculator also shows, is based on the same idea (it covers about 97.5% of healthy adults), so the two values are almost the same. When you cut calories a lot to lose weight, you can drop below this level without noticing. The more you limit your food, the more important it is to keep your protein up on purpose.
TDEE (total daily energy expenditure, the input for the AMDR range)
Figure
Standard notation (the usual math form)
\(T\) \(=\) \(B\) \(\times\) \(k\)
In words (symbols replaced with words)
③ \(T\): total daily energy expenditure (kcal/day) \(=\) ① \(B\): basal metabolic rate (kcal/day) \(\times\) ② \(k\): activity factor
The formula in words
① Take the \(B\): basal metabolic rate (the calories you burn even at complete rest)
② multiply it by the \(k\): activity factor (a multiplier from 1 to 1.9 based on how active you are)
③ and you get the \(T\): total daily energy expenditure (TDEE)
Quick example
A 25-year-old man who is 180 cm (about 5 ft 11 in) tall and weighs 60 kg (about 132 lb) has a BMR of 1,605 kcal/day by the Mifflin-St Jeor formula. If he does light exercise 1–3 times a week (activity factor 1.375), his TDEE is
\(T\): total daily energy expenditure \(=\) BMR (1605) \(\times\) activity factor (1.375)
\(1605 \times 1.375 = 2206.875 \approx 2207\)
Key idea
TDEE, the input for formula 1 (the AMDR range), is calculated inside this calculator as "BMR × activity factor". By default, the BMR \(B\) comes from the Mifflin-St Jeor formula: for men \(B = 10W + 6.25H - 5A + 5\) and for women \(B = 10W + 6.25H - 5A - 161\), where \(W\) is weight in kg, \(H\) is height in cm and \(A\) is age. In pounds and inches, the same formula is \(B = 4.536W + 15.875H - 5A + 5\) for men (\(-161\) instead of \(+5\) for women). If you choose the Katch-McArdle formula, it uses your body fat \(F\) instead (\(B = 370 + 21.6(1-F)W\), with \(W\) in kg). For more on choosing an activity factor and on TDEE itself, see the related "TDEE Calculator" page. To compare BMR formulas, see the "BMR Calculator". If you are unsure, the safer choice is one activity level lower.
In the US, daily protein needs start from two official standards in the Dietary Reference Intakes. The RDA is 0.8 g per kg of body weight (about 0.36 g per lb), and the AMDR is 10–35% of your daily calories. If you exercise regularly, also look at the body-weight guide of 1.0–1.8 g/kg and the WHO safe level (0.83 g/kg), and treat the range where these overlap as your own guide. All of these are estimates for healthy adults; if you have a health condition, the advice of your doctor or registered dietitian comes first.

Symbols and terms

Symbols

\(P\) The daily amount of protein you want to find (g/day), from the first letter of "protein". On this page, formula 1 gives the AMDR range, formula 2 the body-weight guide and formula 3 the RDA.
\(W\) Body weight in kg, from the first letter of "weight". (To convert pounds to kg, divide by about 2.2.)
\(c\) Grams of protein per kg of body weight (g/kg). The guide for people who exercise uses 1.0 to 1.8.
\(r\) The share of your daily calories that comes from protein. The AMDR uses 0.10 to 0.35 (10–35%) for adults. From the first letter of "ratio".
\(T\) TDEE, your total daily energy expenditure (kcal/day). This page uses T for "total".
\(B\) Basal metabolic rate (BMR), an estimate of the calories you burn in a day even at complete rest (kcal/day). From the first letter of "basal".
\(k\) The activity factor, a multiplier for how many times your BMR you burn in a day. This page uses 1 (no activity) and six levels from 1.2 to 1.9.
\(F\) Body fat percentage written as a decimal (for example, 15% → 0.15). Used in the Katch-McArdle formula. From the first letter of "fat".

Terms

protein A nutrient that builds muscles, organs, skin and hair. In the body it also works as enzymes, hormones and antibodies. Meat, fish, eggs, beans, soy foods and dairy products are rich in it. It is made of amino acids linked together.
essential amino acids The 9 amino acids that the body cannot make in large enough amounts, so they must come from food. This is one reason you need protein every day.
RDA (Recommended Dietary Allowance) In the US Dietary Reference Intakes, the daily amount that meets the needs of almost all (97–98%) healthy people. For protein, it is 0.8 g per kg of body weight for adults 19 and older (0.85 g/kg for ages 14 to 18).
AMDR (Acceptable Macronutrient Distribution Range) In the US Dietary Reference Intakes, the range of calories that can come from each macronutrient while lowering the risk of chronic disease and still getting enough of other nutrients. For protein, it is 10–35% of calories for adults (10–30% for ages 4 to 18).
WHO safe level A level of intake (0.83 g per kg of body weight) from a report of the WHO (World Health Organization). It is set statistically to cover about 97.5% of healthy adults. Being a little below it does not mean you are short right away, but use it as a minimum you should not fall below, not as an ideal amount.
TDEE (total daily energy expenditure) The total calories you burn in a day (kcal/day), your BMR plus the calories used for exercise and daily activities. It is estimated as "BMR × activity factor". See the related "TDEE Calculator" page for details.
BMR (basal metabolic rate) The energy you use just to stay alive, for things like keeping your body temperature, breathing and a beating heart (kcal/day). It is the base of TDEE. On this page it is estimated with a formula (Mifflin-St Jeor or Katch-McArdle).
activity factor A multiplier for how many extra calories you use for exercise and daily activities. Multiply your BMR by it to estimate TDEE. This page uses 1 (no activity) and six levels from 1.2 to 1.9.
Atwater factors The energy per gram of each nutrient - about 4 kcal/g for protein, 9 kcal/g for fat and 4 kcal/g for carbohydrate. They are also used for the calories on US Nutrition Facts labels. The AMDR calculation in this calculator uses 4 kcal/g.
DRI (Dietary Reference Intakes) The set of US and Canadian nutrient reference values published by the National Academies of Sciences, Engineering, and Medicine. It includes the RDA and the AMDR. The protein values on this page come from it. The values can change when the DRI are updated.

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.

Multiplying decimals (Grade 5)
  • Being able to multiply with decimals, such as \(60 \times 1.8\) or \(60 \times 0.8\), on paper or with a calculator
  • Knowing that multiplying by a number less than 1 makes the answer smaller (× 0.8 is 20% less)
Percents (Grade 6)
  • Being able to write 10% as 0.10 and 35% as 0.35
  • Being able to find a part by multiplying the whole by a percent, as in "10% of your total calories"
Unit rates (Grade 6)
  • Understanding a unit rate such as "0.8 g per kg of body weight", and being able to explain why multiplying by your weight gives the total
Rounding (Grades 4–5)
  • Being able to round, for example \(108.9\) to the nearest whole number is \(109\)

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 the RDA (US Dietary Reference Intakes)
Weight (lb) 150
Age (years) 25
RDA (g/day) =ROUND(B1*0.45359237*IF(B2>=19,0.8,0.85),0)
Table to find the AMDR range (10–35% of calories)
Sex (male or female) male
Weight (lb) 160
Height (in) 70
Age (years) 25
Activity factor 1.375
BMR (kcal/day) =4.5359237*B2+15.875*B3-5*B4+IF(B1="male",5,-161)
TDEE (kcal/day) =B6*B5
AMDR low end (g/day) =ROUND(B7*0.1/4,0)
AMDR high end (g/day) =ROUND(B7*IF(B4>=19,0.35,0.3)/4,0)
Table to find the body-weight guide (people who exercise) and the WHO safe level
Weight (lb) 150
Guide for people who exercise, low end (g/day) =ROUND(B1*0.454,0)
Guide for people who exercise, high end (g/day) =ROUND(B1*0.816,0)
WHO safe level (g/day) =ROUND(B1*0.376,0)
After pasting, the upper rows are your inputs and the lower rows are calculated automatically. ROUND rounds to a whole number.
In the first table, 0.45359237 turns pounds into kg, and the IF function switches the RDA factor: 0.8 g/kg from age 19, 0.85 g/kg below that. In the second table, the BMR row uses the Mifflin-St Jeor formula in pounds and inches, and its IF function adds 5 if B1 is "male" and subtracts 161 otherwise (female). The last row uses 35% from age 19 and 30% below that.
With the example numbers, the first table gives 54, the second gives a BMR of about 1717, a TDEE of about 2361 and a range of 59 to 207, and the third gives 68, 122 and 56 (the factors 0.454, 0.816 and 0.376 are 1.0, 1.8 and 0.83 g/kg converted to g/lb). Just replace the numbers in column B with your own.

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 the RDA (US Dietary Reference Intakes)
Weight (lb) 150
Age (years) 25
RDA (g/day) =ROUND(B1*0.45359237*IF(B2>=19,0.8,0.85),0)
Table to find the AMDR range (10–35% of calories)
Sex (male or female) male
Weight (lb) 160
Height (in) 70
Age (years) 25
Activity factor 1.375
BMR (kcal/day) =4.5359237*B2+15.875*B3-5*B4+IF(B1="male",5,-161)
TDEE (kcal/day) =B6*B5
AMDR low end (g/day) =ROUND(B7*0.1/4,0)
AMDR high end (g/day) =ROUND(B7*IF(B4>=19,0.35,0.3)/4,0)
Table to find the body-weight guide (people who exercise) and the WHO safe level
Weight (lb) 150
Guide for people who exercise, low end (g/day) =ROUND(B1*0.454,0)
Guide for people who exercise, high end (g/day) =ROUND(B1*0.816,0)
WHO safe level (g/day) =ROUND(B1*0.376,0)
The same formulas as in Excel, including IF and ROUND, work as is. Copy the whole table, paste it into cell A1, and replace the numbers in column B with your own.

How to calculate it in Python

sex = "male"             # "male" or "female"
age = 25                 # age (years)
height_in = 70           # height (inches). 5 ft 10 in = 70 in
weight_lb = 160          # weight (lb)
activity_factor = 1.375  # activity factor (1.2 to 1.9. See the "TDEE Calculator" page for how to choose)

weight_kg = weight_lb * 0.45359237   # pounds to kg

# RDA (US Dietary Reference Intakes): 0.8 g/kg from age 19, 0.85 g/kg at ages 14-18
rda = weight_kg * (0.8 if age >= 19 else 0.85)

# BMR (Mifflin-St Jeor formula in pounds and inches) and TDEE
bmr = 4.5359237 * weight_lb + 15.875 * height_in - 5 * age
bmr = bmr + 5 if sex == "male" else bmr - 161
tdee = bmr * activity_factor

# AMDR: 10-35% of calories (10-30% at ages 14-18), divided by 4 kcal/g to get grams
ratio_max = 0.35 if age >= 19 else 0.30
amdr_min = tdee * 0.10 / 4
amdr_max = tdee * ratio_max / 4

# Reference 1: guide for people who exercise (weight x 1.0-1.8 g/kg)
active_min = weight_kg * 1.0
active_max = weight_kg * 1.8

# Reference 2: WHO safe level (weight x 0.83 g/kg)
who_min = weight_kg * 0.83

print(f"RDA: {round(rda)} g/day")
print(f"AMDR (10-{round(ratio_max * 100)}% of calories): {round(amdr_min)}-{round(amdr_max)} g/day")
print(f"Reference, guide for people who exercise: {round(active_min)}-{round(active_max)} g/day")
print(f"Reference, WHO safe level: {round(who_min)} g/day")
Runs with the standard library only. Change the sex, age, height, weight and activity factor at the top and run it. round() rounds to a whole number (almost the same as ordinary rounding).

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

AMDR range (US Dietary Reference Intakes, 10–35% of calories)
P = r × T ÷ 4
P = \dfrac{r T}{4}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>P</mi><mo>=</mo>
    <mfrac>
      <mrow><mi>r</mi><mi>T</mi></mrow>
      <mn>4</mn>
    </mfrac>
  </mrow>
</math>
P = (r T) / 4
r*t/4
P := r*T/4;
P = r*T/4;
P = rT/4
Body-weight guide (reference: people who exercise)
P = W × c
P = W \times c
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>P</mi><mo>=</mo>
    <mi>W</mi><mo>&#x00D7;</mo><mi>c</mi>
  </mrow>
</math>
P = W xx c
w*c
P := W*c;
P = W*c;
P = W × c
RDA (US Recommended Dietary Allowance, 0.8 g/kg)
P = W × 0.8
P = 0.8W
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>P</mi><mo>=</mo>
    <mn>0.8</mn><mi>W</mi>
  </mrow>
</math>
P = 0.8 W
0.8*w
P := 0.8*W;
P = 0.8*W;
P = 0.8W
TDEE (total daily energy expenditure, the input for the AMDR range)
T = B × k
T = B \times k
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>T</mi><mo>=</mo>
    <mi>B</mi><mo>&#x00D7;</mo><mi>k</mi>
  </mrow>
</math>
T = B xx k
b*k
T := B*k;
T = B*k;
T = B × k

How to have ChatGPT  do the calculation

You are an assistant for protein intake calculations. 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).

A 25-year-old man is 5 ft 10 in tall, weighs 160 lb and does light exercise 1 to 3 times a week (activity factor 1.375).
1. Find his protein RDA from the US Dietary Reference Intakes (0.8 g per kg of body weight for adults; 1 lb = 0.45359237 kg).
2. Find his BMR with the Mifflin-St Jeor formula (men: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5), then multiply by the activity factor 1.375 to get his TDEE (total daily energy expenditure).
3. Find his AMDR range for protein (TDEE × 0.10 to 0.35 ÷ 4 kcal/g).
4. For reference, also find the body-weight guide for people who exercise (weight in kg × 1.0 to 1.8 g/kg) and the WHO safe level (weight in kg × 0.83 g/kg).
Round each value to a whole number and put them in a table, one row per standard.

Show the formulas you used and the numbers from the execution result. Also add a note that these are estimates for healthy adults, not medical advice.

How to Use
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    Type the numbers you want to calculate with into the input fields
  2. 2
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    Press the "Calculate" button
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    Check the result
    The result appears on the spot. The same page also explains the idea behind the calculation and the formula
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