Enter your age, sex, height and weight. You get your basal metabolic rate (BMR, the calories you burn in a day even at complete rest) and estimated calories burned per day at 6 activity levels.
Enter height in cm and weight in kg. The results are estimates from formulas, not medical advice. If you have a health condition, are pregnant or are still growing, talk with a doctor or a registered dietitian.
Result
Enter your age, sex, height and weight on the left and press "Calculate". The result 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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Formula
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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 and weight to see your basal metabolic rate (BMR, the calories you burn in a day even at complete rest) on the spot
- Estimated calories burned per day are also listed for 6 activity levels, from sedentary to a physical job
- You can choose from three BMR formulas: Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle
- A plain-language explanation of what BMR is and how to calculate it, plus copy-and-paste formulas for Excel, Google Sheets and Python, are all on this page
All of these formulas are statistical estimates, so the results are only a rough guide, not medical advice. If you have a health condition, are pregnant or are still growing, talk with a doctor or a registered dietitian before using them. To find a daily calorie target for losing or gaining weight, use the Calorie Calculator in the related pages.
What is this calculation used for?
Knowing the floor so you do not cut too much
When you cut back on food to lose weight, your BMR is one useful reference point: below it, you are not eating enough even to cover just staying alive. Eating far below your BMR for a long time is thought to risk losing muscle and not getting enough nutrients, and extreme diets are said to make weight regain more likely.
Knowing your BMR helps you separate "the amount you can cut" from "the base you should not cut". For planning a specific rate of weight loss, see the Calorie Calculator in the related pages.
Seeing in numbers why it gets easier to gain weight with age
In the Mifflin-St Jeor equation, being 10 years older lowers the estimated BMR by about 50 kcal a day (5 × 10). If you eat the same as when you were younger but your weight is creeping up, this is one reason you can check in numbers.
BMR is also thought to be higher for people with more muscle. That is why the idea behind this formula is used to explain how strength training, by keeping your muscle, can make it easier to stay at a healthy weight.
A base for estimating how much to eat in a day
Without a reference of your own, the calories on a food label do not tell you whether that is a lot or a little. Once you know your calories burned per day (BMR × activity factor), you can see, for example, that for someone who burns 2,000 kcal a day, "this 400-Calorie bakery muffin is a fifth of my day" (the Calories on a US food label are kcal).
In sports nutrition and body composition coaching, meal planning also starts by estimating BMR and then the total calories burned per day.
Used in hospital and long-term care nutrition
To estimate how much energy a hospital patient or an older adult needs in a day, dietitians and doctors have long used BMR formulas such as the Harris-Benedict equation, multiplied by factors for activity and medical condition.
The calculation on this page is the basic form of that method. Real clinical nutrition includes professional adjustments based on the patient's condition and measurements, so always consult a professional about decisions related to treatment or care.
Formula
Basal metabolic rate (Mifflin-St Jeor equation, pounds and inches)
Standard notation
(the usual math form)
\(B\)
\(=\)
\(4.536W\)
\(+\)
\(15.875H\)
\(-\)
\(5A\)
\(+\)
\(5\)
\(B\)
\(=\)
\(4.536W\)
\(+\)
\(15.875H\)
\(-\)
\(5A\)
\(-\)
\(161\)
In words
(symbols replaced with words)
⑤
\(B\): BMR (men)
\(=\)
①
4.536 × \(W\): weight (lb)
\(+\)
②
15.875 × \(H\): height (in)
\(-\)
③
5 × \(A\): age (years)
\(+\)
④
constant for men \(5\)
⑦
\(B\): BMR (women)
\(=\)
4.536 × \(W\): weight (lb)
\(+\)
15.875 × \(H\): height (in)
\(-\)
5 × \(A\): age (years)
\(-\)
⑥
constant for women \(161\)
The formula in words
①
Take
4.536 × \(W\): weight (lb)
②
add
15.875 × \(H\): height (in)
③
subtract
5 × \(A\): age (years)
④
and for men add the
constant for men \(5\)
⑤
to get the
\(B\): BMR (men)
⑥
For women, instead of adding a constant, subtract the
constant for women \(161\)
⑦
to get the
\(B\): BMR (women)
Quick example
For a 25-year-old man who is 5 ft 9 in (69 in) tall and weighs 146 lb, the BMR is
\(B\): BMR (men)
\(=\)
4.536 × weight (146 lb)
\(+\)
15.875 × height (69 in)
\(-\)
5 × age (25)
\(+\)
constant for men (5)
\(4.536 \times 146 + 15.875 \times 69 - 5 \times 25 + 5\)
\(= 662.256 + 1095.375 - 125 + 5 = 1637.631 \approx 1638\)
Key idea
Basal metabolic rate (BMR) is an estimate of the calories you burn in a day at complete rest, for things like keeping your body warm, breathing and keeping your heart beating. It is thought to make up about 60–70% of the calories you burn in a day. It is estimated higher for people with more muscle and lower as you get older.
The Mifflin-St Jeor equation was published in 1990. In studies of people today it is often closer to measured values than older formulas, so it is the default in this calculator. It was published in metric units: \(B = 10W + 6.25H - 5A + 5\) for men and \(- 161\) for women, with \(W\) in kg and \(H\) in cm. The card above is the same formula rewritten for pounds and inches (10 × 0.4536 = 4.536 and 6.25 × 2.54 = 15.875).
You can also choose two other formulas. Both use \(W\) in kg and \(H\) in cm (kg = lb × 0.4536, cm = in × 2.54), and both are statistical estimates with personal differences.
- Revised Harris-Benedict: men \(B = 13.397W + 4.799H - 5.677A + 88.362\); women \(B = 9.247W + 3.098H - 4.330A + 447.593\)
- Katch-McArdle: \(B = 370 + 21.6(1 - F)W\) (\(F\) is body fat percentage as a decimal, for example 20% → 0.20. It is meant for people who know their body fat percentage and does not use sex, age or height.)
In the US, the Dietary Reference Intakes from the National Academies use a different kind of formula, the Estimated Energy Requirement (EER) equations, which estimate total daily calories directly from age, sex, height, weight and activity level. Because the method is different from the three formulas on this page, the numbers can differ somewhat.
Calories burned per day by activity level (BMR × activity factor)
Standard notation
(the usual math form)
In words
(symbols replaced with words)
\(C\)
\(=\)
\(B\)
\(\times\)
\(k\)
③
\(C\): calories burned per day
\(=\)
①
\(B\): BMR
\(\times\)
②
\(k\): activity factor
The formula in words
①
Take the
\(B\): BMR
②
multiply it by the
\(k\): activity factor
③
and you get the
\(C\): calories burned per day
Quick example
For a person with a BMR of 1638 kcal/day (the 25-year-old man above) who gets little or no exercise (activity factor 1.2), the calories burned per day are
\(C\): calories burned per day
\(=\)
BMR (1638)
\(\times\)
activity factor (1.2)
\(1638 \times 1.2 = 1965.6 \approx 1966\)
Key idea
The activity factor is a multiplier that shows how many times your BMR you burn in a day. This calculator uses the following 6 levels and lists the result for every level.
- Sedentary: little or no exercise, desk job → 1.2
- Light: 1–3 workouts a week → 1.375
- Moderate: 4–5 workouts a week → 1.465
- Active: daily exercise, or 3–4 intense workouts a week → 1.55
- Very active: 6–7 intense workouts a week → 1.725
- Extra active: very intense daily exercise or a physical job → 1.9
"BMR × activity factor" is also called total daily energy expenditure (TDEE). In theory, if you eat this many calories, your weight stays the same. People tend to rate their own activity level too high, so if you are unsure, the safer choice is to look at one level lower.
Basal metabolic rate (BMR) is an estimate of the calories you burn in a day at complete rest. Formulas such as the Mifflin-St Jeor equation estimate it from age, sex, height and weight. Multiply it by an activity factor (1.2 to 1.9) to estimate the calories you burn per day at your activity level. Every formula here is an estimate and people differ, so use the results as a rough guide.
Symbols and terms
Symbols
| \(B\) | bee | Basal metabolic rate (BMR), the estimated calories you burn in a day at complete rest (kcal/day). This page uses B, the first letter of "basal". |
| \(W\) | double-u | Weight, from the first letter of "weight". In the formula card on this page it is in pounds (lb); in the original metric formulas it is in kg. |
| \(H\) | aitch | Height, from the first letter of "height". In the formula card on this page it is your total height in inches (5 ft 9 in = 69 in); in the original metric formulas it is in cm. |
| \(A\) | a | Age in years, from the first letter of "age". The older you are, the lower the estimated BMR. |
| \(F\) | ef | Body fat percentage written as a decimal (for example, 20% → 0.20). It is used in the Katch-McArdle formula. F stands for "fat". |
| \(k\) | kay | The activity factor, a multiplier that shows how many times your BMR you burn in a day. This page uses 6 levels between 1.2 and 1.9. |
| \(C\) | see | Calories burned per day at an activity level (kcal/day). C stands for "calories". It is also called total daily energy expenditure (TDEE). |
Terms
| kcal (kilocalorie) | A unit of energy. When food labels and nutrition talk say "calories", they almost always mean kcal. The "Calories" on a US Nutrition Facts label are kcal. 1 kcal is the energy needed to warm 1 liter of water by 1 °C. |
| BMR (basal metabolic rate) | The energy you use just to stay alive, for things like keeping your body warm, breathing and keeping your heart beating (kcal/day). It is thought to make up about 60–70% of the calories you burn in a day. It changes with muscle mass, age, body size and so on. |
| RMR (resting metabolic rate) | The energy you use while resting in a comfortable position. BMR is measured under strict conditions (right after waking up, fully at rest, at least 10 hours after eating), while RMR is measured under looser conditions, so it comes out a little higher than BMR. The two terms sound alike but are different. |
| activity factor | A multiplier for the extra calories you use for exercise and daily activities. You multiply your BMR by it to estimate the total calories you burn in a day. |
| body fat percentage | The share of your body weight that is fat (%). You can measure it with a home body composition scale or similar. The Katch-McArdle formula uses it to estimate BMR. |
| lean body mass | Your body weight minus the fat (muscle, bone, organs and so on). The Katch-McArdle formula is based on the idea that BMR is roughly proportional to lean body mass. |
| Mifflin-St Jeor equation | A formula for estimating BMR, published in 1990. It is often found to be fairly close to measured values in people today and is widely used, including by dietitians in the US. It is the default formula in this calculator. |
| Harris-Benedict equation | A classic formula for estimating BMR, published in 1919. This page uses the revised version, whose numbers were updated in 1984. |
| Katch-McArdle formula | A formula that estimates BMR from lean body mass. It is considered accurate for people who know their body fat percentage well. Its strength is that it reflects differences in muscle mass. |
| EER (Estimated Energy Requirement) | The daily calories estimated to keep a healthy person's weight steady, used in the Dietary Reference Intakes from the US National Academies. It is found with equations that use age, sex, height, weight and activity level. The equations have been revised over time, so check the latest National Academies report for current values. |
| TDEE (total daily energy expenditure) | The total calories you burn in a day, your BMR plus the calories for exercise and daily activities. It is usually estimated as "BMR × activity factor". |
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 (Grades 5–6) |
|
| Percentages (Grade 6) |
|
| Rounding (Grade 4) |
|
| Adding and subtracting larger numbers (Grades 3–4) |
|
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 BMR (Mifflin-St Jeor equation)
| Sex (M or F) | M |
| Weight (lb) | 146 |
| Height (in) | 69 |
| Age (years) | 25 |
| BMR (kcal/day) | =4.536*B2+15.875*B3-5*B4+IF(B1="M",5,-161) |
Table to find the calories burned per day by activity level
| BMR (kcal/day) | 1638 |
| Sedentary: little or no exercise (×1.2) | =ROUND(B1*1.2,0) |
| Light: 1–3 workouts a week (×1.375) | =ROUND(B1*1.375,0) |
| Moderate: 4–5 workouts a week (×1.465) | =ROUND(B1*1.465,0) |
| Active: daily exercise, or 3–4 intense workouts a week (×1.55) | =ROUND(B1*1.55,0) |
| Very active: 6–7 intense workouts a week (×1.725) | =ROUND(B1*1.725,0) |
| Extra active: very intense daily exercise or a physical job (×1.9) | =ROUND(B1*1.9,0) |
After pasting, the upper rows are your inputs. The last row of the first table and B2 to B7 of the second table are calculated automatically.
The IF function in the first table switches the constant by sex: if B1 is "M" it adds 5, otherwise (F) it subtracts 161. Weight is in pounds and height is your total height in inches (5 ft 9 in = 69). ROUND in the second table rounds to a whole number.
With the example numbers, the first table gives 1637.631 (about 1638), and the second table gives 1966, 2252, 2400, 2539, 2826 and 3112 from top to bottom. Just replace the numbers in column B with your own.
The IF function in the first table switches the constant by sex: if B1 is "M" it adds 5, otherwise (F) it subtracts 161. Weight is in pounds and height is your total height in inches (5 ft 9 in = 69). ROUND in the second table rounds to a whole number.
With the example numbers, the first table gives 1637.631 (about 1638), and the second table gives 1966, 2252, 2400, 2539, 2826 and 3112 from top to bottom. 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 BMR (Mifflin-St Jeor equation)
| Sex (M or F) | M |
| Weight (lb) | 146 |
| Height (in) | 69 |
| Age (years) | 25 |
| BMR (kcal/day) | =4.536*B2+15.875*B3-5*B4+IF(B1="M",5,-161) |
Table to find the calories burned per day by activity level
| BMR (kcal/day) | 1638 |
| Sedentary: little or no exercise (×1.2) | =ROUND(B1*1.2,0) |
| Light: 1–3 workouts a week (×1.375) | =ROUND(B1*1.375,0) |
| Moderate: 4–5 workouts a week (×1.465) | =ROUND(B1*1.465,0) |
| Active: daily exercise, or 3–4 intense workouts a week (×1.55) | =ROUND(B1*1.55,0) |
| Very active: 6–7 intense workouts a week (×1.725) | =ROUND(B1*1.725,0) |
| Extra active: very intense daily exercise or a physical job (×1.9) | =ROUND(B1*1.9,0) |
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 = 69 # height (total inches: 5 ft 9 in = 69)
weight_lb = 146 # weight (lb)
# BMR (Mifflin-St Jeor equation, pounds and inches)
bmr = 4.536 * weight_lb + 15.875 * height_in - 5 * age
bmr = bmr + 5 if sex == "male" else bmr - 161
print(f"BMR: {round(bmr)} kcal/day")
# Calories burned per day by activity level (BMR x activity factor)
levels = [("Sedentary: little or no exercise, desk job", 1.2), ("Light: 1-3 workouts a week", 1.375),
("Moderate: 4-5 workouts a week", 1.465), ("Active: daily exercise, or 3-4 intense workouts a week", 1.55),
("Very active: 6-7 intense workouts a week", 1.725), ("Extra active: very intense daily exercise or a physical job", 1.9)]
for label, factor in levels:
print(f"{label} (x{factor}): {round(bmr * factor)} kcal/day")
Runs with the standard library only. Change the sex, age, height and weight at the top and run it. round() rounds to a whole number (almost the same as rounding half up). To use the revised Harris-Benedict or Katch-McArdle formula, replace the two lines that find bmr with the formula from the "Formula" section (those formulas use kg and cm, so convert with kg = lb × 0.4536 and cm = in × 2.54 first).
How to write it in LaTeX and other math languages (copy and paste)
Basal metabolic rate (Mifflin-St Jeor equation, pounds and inches)
B = 4.536W + 15.875H − 5A + 5 (men), B = 4.536W + 15.875H − 5A − 161 (women)
B_{m} = 4.536W + 15.875H - 5A + 5, \quad B_{f} = 4.536W + 15.875H - 5A - 161
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<msub><mi>B</mi><mi>m</mi></msub>
<mo>=</mo>
<mn>4.536</mn><mi>W</mi>
<mo>+</mo>
<mn>15.875</mn><mi>H</mi>
<mo>−</mo>
<mn>5</mn><mi>A</mi>
<mo>+</mo>
<mn>5</mn>
<mo>,</mo>
<msub><mi>B</mi><mi>f</mi></msub>
<mo>=</mo>
<mn>4.536</mn><mi>W</mi>
<mo>+</mo>
<mn>15.875</mn><mi>H</mi>
<mo>−</mo>
<mn>5</mn><mi>A</mi>
<mo>−</mo>
<mn>161</mn>
</mrow>
</math>
B_m = 4.536W + 15.875H - 5A + 5, B_f = 4.536W + 15.875H - 5A - 161
{4.536*w + 15.875*h - 5*a + 5, 4.536*w + 15.875*h - 5*a - 161}
Bm := 4.536*W + 15.875*H - 5*A + 5; Bf := 4.536*W + 15.875*H - 5*A - 161;
B_m = 4.536*W + 15.875*H - 5*A + 5; B_f = 4.536*W + 15.875*H - 5*A - 161;
B_m = 4.536W + 15.875H - 5A + 5, B_f = 4.536W + 15.875H - 5A - 161
Calories burned per day by activity level (BMR × activity factor)
C = B × k
C = B \times k
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>C</mi><mo>=</mo>
<mi>B</mi><mo>×</mo><mi>k</mi>
</mrow>
</math>
C = B xx k
b*k
C := B*k;
C = B*k;
C = B × k
How to have ChatGPT do the calculation
You are a BMR calculation assistant. 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 9 in tall and weighs 146 lb. 1. Convert his weight to kg (1 lb = 0.45359237 kg) and his height to cm (1 in = 2.54 cm), then find his basal metabolic rate (BMR) with the Mifflin-St Jeor equation (men: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5). 2. Multiply that BMR by each of the activity factors 1.2, 1.375, 1.465, 1.55, 1.725 and 1.9, and round to the nearest whole number to find the calories burned per day at each activity level. Show the formulas you used and the numbers from the execution result. Also note that these are estimates from formulas and 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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