What is a normal BMR?

It depends on size, age and sex. Many adult women fall around 1,200–1,500 kcal/day and many adult men around 1,500–1,900 kcal/day.

Which BMR formula is most accurate?

For most healthy adults, Mifflin-St Jeor. Katch-McArdle can be better if you know your body fat percentage and are leaner or more muscular than average.

Is BMR the same as RMR?

Nearly. Resting metabolic rate is measured under looser conditions and runs slightly higher, so the terms are often used interchangeably.

Should I eat my BMR to lose weight?

Usually no. BMR leaves out all daily activity, so eating at BMR is often a large deficit. Use the calorie deficit calculator to set a target from your TDEE.

Why does BMR fall with age?

Each formula subtracts a set amount per year of age, reflecting a typical loss of lean mass. Strength training can slow that loss.

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BMR Calculator

Your basal metabolic rate (BMR) is the energy your body uses at complete rest to breathe, circulate blood and keep organs working. It is usually 60–70% of the calories you burn in a day.

BMR formulas

Mifflin-St Jeor (1990): men 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5; women the same with − 161 at the end. It is the default because it tracks measured BMR most closely in studies of healthy adults.

Revised Harris-Benedict (Roza and Shizgal, 1984): men 13.397W + 4.799H − 5.677A + 88.362; women 9.247W + 3.098H − 4.330A + 447.593. It tends to run a little higher than Mifflin-St Jeor.

Katch-McArdle: 370 + 21.6 × lean body mass (kg). Because it uses lean mass instead of age and sex, it can be more accurate for very lean or muscular people who know their body fat percentage.

Example

A 35-year-old man, 5 ft 10 in and 180 lb: Mifflin-St Jeor gives 1,758 kcal/day and revised Harris-Benedict 1,837. At 22% body fat, Katch-McArdle gives 1,746.

To turn BMR into the calories you actually need, multiply by an activity factor, or use the TDEE calculator.

These are estimates for healthy adults, not medical advice. If you are pregnant or breastfeeding, under 18, or managing a medical condition or an eating disorder, ask a doctor or registered dietitian before changing how much you eat.

BMR by age (Mifflin-St Jeor), 5 ft 10 in and 180 lb vs 5 ft 5 in and 150 lb
Age	Man, 5 ft 10 in, 180 lb	Woman, 5 ft 5 in, 150 lb
20	1,833	1,451
30	1,783	1,401
40	1,733	1,351
50	1,683	1,301
60	1,633	1,251
70	1,583	1,201

Frequently asked questions

What is a normal BMR?: It depends on size, age and sex. Many adult women fall around 1,200–1,500 kcal/day and many adult men around 1,500–1,900 kcal/day.
Which BMR formula is most accurate?: For most healthy adults, Mifflin-St Jeor. Katch-McArdle can be better if you know your body fat percentage and are leaner or more muscular than average.
Is BMR the same as RMR?: Nearly. Resting metabolic rate is measured under looser conditions and runs slightly higher, so the terms are often used interchangeably.
Should I eat my BMR to lose weight?: Usually no. BMR leaves out all daily activity, so eating at BMR is often a large deficit. Use the calorie deficit calculator to set a target from your TDEE.
Why does BMR fall with age?: Each formula subtracts a set amount per year of age, reflecting a typical loss of lean mass. Strength training can slow that loss.