Enter your age, sex, height, weight, activity level and goal. Your maintenance calories (TDEE) and calories for each goal are calculated, and the daily grams of carbs for each share (40%, 50%, 60% and 65%; the US AMDR is 45–65%) are shown in a bar graph and a table.
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 what you eat, are pregnant or are still growing, talk with a doctor or a registered dietitian.
Result and graph
Enter your age, sex, height, weight and goal in the fields on the left and press "Calculate". The result and a bar graph will appear here.
Table of Contents
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What you can do on this page
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What is this calculation used for?
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How to Use
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Formulas and figures
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Symbols and terms
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Good to know before you start
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How to calculate it in Excel
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How to calculate it in Google Sheets
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How to calculate it in Python
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How to write it in LaTeX and other math languages (copy and paste)
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How to have ChatGPT do the calculation
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DataChef Features
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Related Features
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NumberChef Calculators List
What you can do on this page
- Enter your age, sex, height, weight and activity level, and you see on the spot your maintenance calories (TDEE) and how many grams of carbs to eat per day for each goal (lose, maintain or gain)
- The results come in a table of 5 goals (maintain, lose about 1 lb or 2 lb a week, gain about 1 lb or 2 lb a week) × 4 carb shares (40%, 50%, 60% and 65% of calories)
- The main standard is the AMDR of the US Dietary Reference Intakes: 45–65% of your calories from carbs. A bar graph shows the grams for each share for your chosen goal, and whether each share is inside the AMDR
- Calories are turned into grams with 4 kcal/g (the Atwater factor, the same standard factor used for US Nutrition Facts labels)
- A plain-language explanation of the formulas and copy-and-paste formulas for Excel, Google Sheets and Python are all on this page
The results are estimates for healthy adults based on formulas. Everyone is different, and this is not medical advice. If you have a condition that calls for limiting or adjusting what you eat, such as diabetes or 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?
Fueling plans for endurance sports such as running and cycling
In long endurance exercise, the main fuel is sugar stored in the muscles and liver (glycogen). So in sports nutrition, carbs are often planned higher, in share and in grams, during periods of heavy training. The higher columns on this page, such as 60% and 65% (the top of the AMDR), can be read as a guide for those "very active days".
"Carb loading", eating extra carbs before a race to store up glycogen, also starts from the same calculation, "calories × share ÷ calories per gram". Detailed planning for competition is a job for experts such as sports dietitians, but knowing your usual amount in numbers is a good starting point for that talk.
A yardstick to keep low-carb dieting from going too far
Many people cut carbs first when they want to lose weight. But carbs are the main energy source for the brain and body, and cutting too much can cause headaches, poor focus and constipation. Based on how much glucose the brain needs, the US Dietary Reference Intakes set an RDA of 130 g a day of carbohydrate for adults.
If you look at the grams for 40% (a lower share) at your own calorie target on this page, you can judge with numbers, not by feel, where the AMDR ends and "lower carb" begins. 40% is below the AMDR (45–65%), and if you want to cut much further than that, it is safer to talk with a health professional.
Picturing your daily carbs as rice and bread
A number like "250 g a day" is hard to picture, but it becomes concrete when you turn it into everyday foods. For example, 1 cup of cooked white rice has about 45 g of carbs, and a slice of bread has about 15 g. People with diabetes often learn to count carbs in "carb choices" of 15 g each. With a daily guide of 250 g, that is about 17 carb choices spread across the day.
Nutrition Facts labels always list "Total Carbohydrate" in grams. If you know your own daily guide, you can tell on the spot what share of your day a food is.
Carb counting in medical nutrition care
In diabetes care, "carb counting", which means counting the grams of carbs in each meal to manage changes in blood sugar, is a common method. Knowing your carbs in grams is an important skill in medical care too.
However, setting the amount of carbs as part of treatment is done one person at a time by a doctor or registered dietitian, based on the body and the medicines used. The calculation on this page is a general guide for healthy adults. If you are under treatment, always follow your doctor's instructions, not these numbers.
Turning a weight-gain phase into a plan for how much to eat
To build muscle in a weight-gain phase, you need to train and also eat more calories than you burn, and carbs cover much of those extra calories. The row for gaining about 1 lb a week (+500 kcal a day) shows in numbers that you need several dozen grams more carbs a day than when maintaining (at 50%, \(500 \times 0.5 \div 4 = 62.5\) g more).
You can even see "how many more grams of grains or bread to add", so it helps you plan a weight gain instead of just eating more at random.
Formulas and figures
Daily calorie target (TDEE and goal adjustment)
Figure
Standard notation
(the usual math form)
\(E\)
\(=\)
\(B\)
\(\times\)
\(k\)
\(+\)
\(a\)
In words
(symbols replaced with words)
④
\(E\): daily calorie target (kcal/day)
\(=\)
①
\(B\): basal metabolic rate (kcal/day)
\(\times\)
②
\(k\): activity factor
\(+\)
③
\(a\): goal adjustment (kcal/day)
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 1.2 to 1.9 based on how active you are)
to get your maintenance calories (TDEE)
③
add the
\(a\): goal adjustment (negative to lose weight, positive to gain)
④
and you get the
\(E\): daily calorie target
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 keeps doing light exercise (activity factor 1.375) and aims to lose weight (an adjustment of −500 kcal, about 1 lb a week), his calorie target is
\(E\): daily calorie target
\(=\)
BMR (1605)
\(\times\)
activity factor (1.375)
\(+\)
adjustment (−500)
\(1605 \times 1.375 = 2206.875 \approx 2207\)
\(2207 - 500 = 1707\)
Key idea
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 finds your lean body mass from your body fat \(F\) and uses \(B = 370 + 21.6(1-F)W\) (with \(W\) in kg). For details, see the related "TDEE Calculator" page.
The goal adjustment \(a\) is 0 to maintain, ±500 kcal for about 1 lb a week and ±1,000 kcal for about 2 lb a week. This comes from the common rule of thumb that 1 lb of body fat is roughly 3,500 kcal, so cutting 500 kcal a day for a week (\(500 \times 7 = 3500\)) is about 1 lb of fat. In metric units, the same rule of thumb is about 7,700 kcal per kg, so the metric goals (0.5 and 1 kg a week) use the same rounded 500 and 1,000 kcal. Real weight change also depends on water and muscle, so it may not follow this rule exactly.
With fast weight loss (about 2 lb a week), your calorie target can fall below your BMR. Losing weight too fast can cost you muscle and make you feel unwell, so this calculator shows a warning. It is a good idea to start at a comfortable pace (up to 1 lb a week).
Daily grams of carbs (share and calories per gram)
Figure
Standard notation
(the usual math form)
\(G\)
\(=\)
\(E\)
\(\times\)
\(r\)
\(\div\)
\(4\)
In words
(symbols replaced with words)
④
\(G\): grams of carbs (g/day)
\(=\)
①
\(E\): daily calorie target (kcal/day)
\(\times\)
②
\(r\): share of calories from carbs
\(\div\)
③
4: calories per gram (kcal/g)
The formula in words
①
Out of the
\(E\): daily calorie target
②
take the part given by the
\(r\): share of calories from carbs (40%, 50%, 60% or 65% on this page)
③
divide it by the
4: calories per gram (1 g of carbs is about 4 kcal)
to turn calories into grams
④
and you get the
\(G\): grams of carbs
Quick example
For a person with a daily calorie target of 1,707 kcal who gets 60% of it from carbs (inside the AMDR), the grams of carbs are
\(G\): grams of carbs
\(=\)
calorie target (1707)
\(\times\)
share (0.60)
\(\div\)
calories per gram (4)
\(1707 \times 0.60 = 1024.2\)
\(1024.2 \div 4 = 256.05 \approx 256\)
Key idea
The main standard for the share \(r\) is the AMDR of the US Dietary Reference Intakes: 45–65% of calories from carbohydrate for adults. On this page, 50% and 60% are inside the range and 65% is the top. 40% is below the range, a "lower carb" reference value. If you are unsure, start with the 50%, 60% and 65% columns.
The Dietary Reference Intakes also set an RDA for carbohydrate of 130 g a day for adults, based on the amount of glucose the brain needs. For comparison, the Daily Value on Nutrition Facts labels is 275 g, based on a 2,000-calorie diet.
The calories per gram tell you how many kcal 1 g of carbs has. This calculator uses 4 kcal/g, the standard Atwater factor that is also used for the calories on US Nutrition Facts labels.
The grams are calculated from the calories before TDEE is rounded. The calorie target on the screen is a rounded whole number, so if you calculate by hand from it, the result can very rarely be 1 g off.
Your daily carbs take 3 steps: (1) set your daily calorie target (BMR × activity factor + goal adjustment), (2) choose the share of calories from carbs, and (3) divide by 4 kcal/g (the Atwater factor) to get grams. Use the US AMDR (45–65% of calories) as your guide for the share. If you have a health condition, the advice of your doctor or registered dietitian comes first.
Symbols and terms
Symbols
| \(E\) | Your daily calorie target (kcal/day), your maintenance calories (TDEE) plus the goal adjustment. Part of it comes from carbs. From the first letter of "energy". |
| \(B\) | 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 six levels from 1.2 to 1.9. |
| \(a\) | The goal adjustment (kcal/day). It is 0 to maintain, negative to lose weight (−500 or −1,000) and positive to gain (+500 or +1,000). From the first letter of "adjustment". |
| \(r\) | The share of your daily calorie target that comes from carbs (for example, 0.60 for 60%). From the first letter of "ratio". |
| \(G\) | The daily grams of carbs you want to find (g/day). From the first letter of "gram". |
| \(W\) | Body weight in kg, used in the BMR formula (in pounds for the pounds-and-inches version). From the first letter of "weight". |
| \(H\) | Height in cm, used in the BMR formula (in inches for the pounds-and-inches version). From the first letter of "height". |
| \(A\) | Age in years, used in the BMR formula. From the first letter of "age". |
| \(F\) | Body fat percentage written as a decimal (for example, 20% → 0.20). Used in the Katch-McArdle formula. From the first letter of "fat". |
Terms
| carbohydrate (carbs) | The main energy source for the body and brain. Rice, bread, pasta, potatoes, fruit and sugar are rich in it. It includes sugars and starches, which are digested for energy, and fiber, which is hard to digest. Along with protein and fat, it is one of the 3 macronutrients. |
| net carbs | The part of carbohydrate that is digested and absorbed for energy (such as glucose), roughly total carbohydrate minus fiber. It is made up mainly of sugars, such as table sugar, and starches, found in rice and potatoes. Low-carb diets often count this. It is a popular term, not an official label term. |
| fiber | The part of carbohydrate that human digestive enzymes can hardly digest. Vegetables, beans and whole grains are rich in it, and it helps keep your gut working well. It adds almost no calories. The US guide for adults is about 14 g per 1,000 kcal. |
| refined carbs | Carbs such as white rice and white bread, where fiber and other parts are removed during processing. For the same grams, they have less fiber and fewer vitamins than whole grains, and they are said to raise blood sugar faster. |
| whole grains | Grains such as brown rice, oatmeal and whole-wheat bread, which keep their fiber and other parts. For the same grams, they have more fiber and vitamins than refined carbs, and blood sugar is said to rise more slowly. The Dietary Guidelines for Americans advise making at least half your grains whole grains. |
| 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". It is also called maintenance calories. 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). 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 six levels from 1.2 to 1.9. |
| lean body mass | The weight of your muscles, bones, organs and so on, which is your body weight minus your body fat. It is found as weight × (1 − body fat percentage). The Katch-McArdle formula estimates BMR from this value. |
| Atwater factors | The energy per gram of each nutrient. Carbohydrate has 4 kcal/g, the standard value also used for the calories on US Nutrition Facts labels. This calculator uses the same 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. For carbohydrate, it sets an AMDR of 45–65% of calories and an RDA of 130 g a day for adults. The shares on this page are based on it. |
| AMDR (Acceptable Macronutrient Distribution Range) | In the 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 carbohydrate, it is 45–65% of calories for adults. On this page, the 50%, 60% and 65% columns are inside this range. |
| Japanese standard (for comparison) | For comparison, Japan's official standard (the Dietary Reference Intakes for Japanese, 2025) sets a goal of 50–65% of calories from carbohydrate, which mostly overlaps with the US AMDR of 45–65%. The calculations on this page use the US AMDR. |
| low-carb diet | A way of eating that keeps the share of calories from carbohydrate low on purpose. The 40% on this page is below the AMDR (45–65%), but it is still much more than many low-carb diets, which often aim for less than 130 g a day, and very low-carb (ketogenic) diets, which often aim for less than about 50 g a day. Strict limits can cause problems such as headaches and constipation and can throw off your nutrition, so it is safer to talk with a health professional first. |
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 (Grade 6) |
|
| Multiplying and dividing decimals (Grades 5–6) |
|
| Positive and negative numbers (Grade 7) |
|
| Rounding (Grades 4–5) |
|
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 daily calorie target
| Sex (male or female) | male |
| Weight (lb) | 160 |
| Height (in) | 70 |
| Age (years) | 25 |
| Activity factor | 1.375 |
| Goal adjustment (kcal/day; 0 to maintain, negative to lose) | -500 |
| BMR (kcal/day) | =4.5359237*B2+15.875*B3-5*B4+IF(B1="male",5,-161) |
| TDEE, maintenance calories (kcal/day) | =ROUND(B7*B5,0) |
| Daily calorie target (kcal/day) | =B8+B6 |
Table to find the daily grams of carbs
| Daily calorie target (kcal/day) | 1861 |
| Share of calories from carbs (for 60%, enter 0.6) | 0.6 |
| Grams of carbs (g/day) | =ROUND(B1*B2/4,0) |
After pasting, the upper rows are your inputs and the lower rows are calculated automatically. ROUND rounds to a whole number.
The BMR row in the first table uses the Mifflin-St Jeor formula in pounds and inches. Its IF function adds 5 if B1 is "male" and subtracts 161 otherwise (female). With the example numbers, you get a BMR of about 1717, a TDEE of 2361 and a calorie target of 1861.
The second table uses a share of 60%, which is inside the US AMDR (45–65%), and gives 279 g/day of carbs. Change B2 to 0.4 and you get 186, 0.5 gives 233 and 0.65 gives 302, which rebuilds one row of this page's table. Just replace the numbers in column B with your own.
This page's calculator works out the grams from TDEE before rounding, so near a rounding boundary, this table (which rounds TDEE first) can very rarely be 1 g off.
The BMR row in the first table uses the Mifflin-St Jeor formula in pounds and inches. Its IF function adds 5 if B1 is "male" and subtracts 161 otherwise (female). With the example numbers, you get a BMR of about 1717, a TDEE of 2361 and a calorie target of 1861.
The second table uses a share of 60%, which is inside the US AMDR (45–65%), and gives 279 g/day of carbs. Change B2 to 0.4 and you get 186, 0.5 gives 233 and 0.65 gives 302, which rebuilds one row of this page's table. Just replace the numbers in column B with your own.
This page's calculator works out the grams from TDEE before rounding, so near a rounding boundary, this table (which rounds TDEE first) can very rarely be 1 g off.
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 daily calorie target
| Sex (male or female) | male |
| Weight (lb) | 160 |
| Height (in) | 70 |
| Age (years) | 25 |
| Activity factor | 1.375 |
| Goal adjustment (kcal/day; 0 to maintain, negative to lose) | -500 |
| BMR (kcal/day) | =4.5359237*B2+15.875*B3-5*B4+IF(B1="male",5,-161) |
| TDEE, maintenance calories (kcal/day) | =ROUND(B7*B5,0) |
| Daily calorie target (kcal/day) | =B8+B6 |
Table to find the daily grams of carbs
| Daily calorie target (kcal/day) | 1861 |
| Share of calories from carbs (for 60%, enter 0.6) | 0.6 |
| Grams of carbs (g/day) | =ROUND(B1*B2/4,0) |
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)
goal_adjust = -500 # goal adjustment (kcal/day. 0 to maintain, negative to lose, positive to gain)
# BMR (Mifflin-St Jeor formula in pounds and inches) -> TDEE -> daily calorie target
bmr = 4.5359237 * weight_lb + 15.875 * height_in - 5 * age
bmr = bmr + 5 if sex == "male" else bmr - 161
tdee = bmr * activity_factor # TDEE before rounding (used for the grams)
calories = tdee + goal_adjust # calorie target before rounding
print(f"Maintenance calories (TDEE): {round(tdee)} kcal/day")
print(f"Daily calorie target: {round(calories)} kcal/day")
# Grams of carbs for 4 shares (the US AMDR is 45-65%).
# 4 kcal/g is the Atwater factor. Work from the unrounded calories and round only at the end
for ratio_pct in [40, 50, 60, 65]:
carb_g = round(calories * ratio_pct / 100 / 4)
print(f"Getting {ratio_pct}% of calories from carbs: {carb_g} g/day")
Runs with the standard library only. Change the sex, age, height, weight, activity factor and goal adjustment at the top and run it. round() rounds to a whole number (almost the same as ordinary rounding). With the example numbers, you get a TDEE of 2361 and a calorie target of 1861, and carbs of 186 at 40%, 233 at 50%, 279 at 60% and 302 at 65% (g/day).
How to write it in LaTeX and other math languages (copy and paste)
Daily calorie target (TDEE and goal adjustment)
E = B × k + a
E = B \times k + a
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>E</mi><mo>=</mo>
<mi>B</mi><mo>×</mo><mi>k</mi>
<mo>+</mo><mi>a</mi>
</mrow>
</math>
E = B xx k + a
b*k + a
E := B*k + a;
E = B*k + a;
E = B × k + a
Daily grams of carbs (share and calories per gram)
G = E × r ÷ 4
G = \dfrac{E \times r}{4}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>G</mi><mo>=</mo>
<mfrac>
<mrow><mi>E</mi><mo>×</mo><mi>r</mi></mrow>
<mn>4</mn>
</mfrac>
</mrow>
</math>
G = (E xx r) / 4
e*r/4
G := E*r/4;
G = E*r/4;
G = E × r / 4
How to have ChatGPT do the calculation
You are an assistant for carbohydrate 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 (activity factor 1.375). He wants to lose about 1 lb a week (−500 kcal a day). 1. Find his BMR with the Mifflin-St Jeor formula (men: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5; 1 lb = 0.45359237 kg, 1 in = 2.54 cm), multiply by the activity factor 1.375 and round to a whole number (TDEE), then add −500 kcal to get his daily calorie target. 2. For 40%, 50%, 60% and 65% of the calorie target coming from carbs, divide each by 4 kcal/g (the Atwater factor) and round to a whole number to get the daily grams. 3. The AMDR for carbohydrate in the US Dietary Reference Intakes is 45–65% of calories. Show which of the 4 shares are inside this range. Show the formulas you used and the numbers from the execution result in a table. Also add a note that these are estimates for healthy adults, not medical advice.
How to Use
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1Enter your numbersType the numbers you want to calculate with into the input fields
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2CalculatePress the "Calculate" button
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3Check the resultThe result appears on the spot. The same page also explains the idea behind the calculation and the formula
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