DailyCalc

BMR Calculator

Estimate the calories your body burns at complete rest.

Units
Sex
years
kg
cm
%

Only if you know it reliably, for example from a DEXA scan.

Basal metabolic rate (Mifflin-St Jeor)

1,649 kcal/day

6,898 kJ/day

Your body burns about 1,649 kcal (6,898 kJ) a day at complete rest, by the Mifflin-St Jeor equation.

Three formulas side by side
Formulakcal/daykJ/day
Mifflin-St Jeor (1990), our default1,6496,898
Revised Harris-Benedict (1984)1,6967,095
Katch-McArdle (lean mass)Add body fat %Add body fat %

The formulas differ by 47 kcal a day for you.

This is your burn at complete rest. For your daily total with activity, use the calorie calculator (TDEE).

Fix the highlighted field to update the result.

Show the working and the original 1919 equation

10 × 70 kg + 6.25 × 175 cm − 5 × 30 + 5 = 1,649 kcal a day

Original Harris-Benedict (1919): 1,702 kcal (7,121 kJ). Mifflin’s 1990 study found it overestimated measured resting energy by about 5%.

Katch-McArdle uses only lean mass, so it ignores age and sex.

How to use

  1. Choose Metric or Imperial and enter your sex, age, weight and height.
  2. Optional: add your body fat % to see the Katch-McArdle estimate.
  3. Compare the formulas. Mifflin-St Jeor is the headline result.

BMR formulas

Mifflin-St Jeor (1990)
  Men:   10 × W + 6.25 × H − 5 × A + 5
  Women: 10 × W + 6.25 × H − 5 × A − 161

Revised Harris-Benedict (Roza & Shizgal, 1984)
  Men:   88.362 + 13.397 × W + 4.799 × H − 5.677 × A
  Women: 447.593 + 9.247 × W + 3.098 × H − 4.330 × A

Katch-McArdle
  370 + 21.6 × lean mass (kg)

W is weight in kg, H is height in cm and A is age in years. Lean mass = weight × (1 − body fat % ÷ 100).

A 2005 systematic review found Mifflin-St Jeor the most reliable of the common equations, so it is our default.

Examples

Person Mifflin-St Jeor Harris-Benedict Katch-McArdle
Man, 25, 180 cm, 80 kg, 15% fat 1,805 1,882 1,839
Woman, 30, 165 cm, 60 kg, 25% fat 1,320 1,384 1,342

All values are kcal a day.

Katch-McArdle by body fat (80 kg)

Body fat Lean mass BMR (kcal/day)
10% 72 kg 1,925
15% 68 kg 1,839
20% 64 kg 1,752
25% 60 kg 1,666
30% 56 kg 1,580

BMR, RMR and TDEE

  • BMR: energy used at complete rest, measured just after waking and fasting.
  • RMR: a looser resting measure, about 10% higher than BMR.
  • TDEE: your total daily burn, adding digestion and activity.
Formula history and names

The original Harris-Benedict equations date from 1919. Mifflin’s 1990 study found they overestimated measured resting energy by about 5%, so we show them only in the working.

“Katch-McArdle” is named after the exercise physiology textbook that presents it. The same equation was published by Cunningham in 1991.

Want your daily total with activity? Use the calorie calculator.

Frequently asked questions

What is BMR?

BMR (basal metabolic rate) is the energy your body uses at complete rest to stay alive: breathing, circulation, temperature and cell repair. Resting energy is usually 60–70% of your daily burn.

What’s the difference between BMR, RMR and TDEE?

BMR is measured at complete rest, straight after waking and fasting. RMR uses looser conditions and runs about 10% higher. TDEE adds digestion and activity: your total daily burn.

Which BMR formula is most accurate?

Mifflin-St Jeor, for most adults. A 2005 systematic review found it predicted resting rate within 10% of measured for more people than other common equations, though individual errors remain.

When should I use the Katch-McArdle formula?

Use it only if you know your body fat percentage reliably. It works from lean body mass, which explains most of the differences in resting energy between people.

How does body fat percentage change the Katch-McArdle result?

More body fat means less lean mass, so a lower estimate. For an 80 kg person, Katch-McArdle gives about 1,925 kcal a day at 10% body fat and 1,666 kcal at 25%.

Why do the formulas give different answers?

They come from different groups of people, measured decades apart. Mifflin’s 1990 study found the 1919 Harris-Benedict equations overestimated measured resting energy by about 5%.

Embed this calculator

Add this calculator to your own website for free. Copy the code below and paste it into your page’s HTML. The attribution link is optional.