BMR Calculator

Estimate how many calories your body burns at complete rest. Compare the Mifflin-St Jeor and Harris-Benedict formulas side by side.

Units
Sex
Your BMR (Mifflin-St Jeor)
–
Harris-Benedict (revised)–
Per hour at rest–

BMR is energy at complete rest. Your daily needs are higher once you add activity.

What your BMR means

Even lying still all day, your body uses energy to breathe, pump blood, repair cells and keep your temperature steady. That baseline is your basal metabolic rate. For most people it makes up the largest share of the calories they burn each day.

BMR formulas

Mifflin-St Jeor
Men: 10 × kg + 6.25 × cm − 5 × age + 5
Women: 10 × kg + 6.25 × cm − 5 × age − 161
Harris-Benedict (revised 1984)
Men: 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age
Women: 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age

Worked example

A 30-year-old woman who is 165 cm tall and weighs 60 kg has a Mifflin-St Jeor BMR of 10 × 60 + 6.25 × 165 − 5 × 30 − 161 = 1,320 calories a day.

What affects BMR

  • Body size: larger bodies need more energy.
  • Muscle: more lean muscle raises BMR.
  • Age: BMR usually declines gradually with age.
  • Sex: men tend to have higher BMRs, mostly because of more muscle on average.

To include activity and see your full daily calorie needs, use the TDEE calculator. This tool is for general information only and is not medical advice.

Last reviewed October 2026.

Frequently asked questions

What is BMR?

Basal metabolic rate (BMR) is the number of calories your body needs at complete rest to keep basic functions going, such as breathing, circulation and keeping warm. It does not include any activity.

What is the difference between BMR and TDEE?

BMR is the energy you use at rest. TDEE (total daily energy expenditure) adds everything you do during the day, from walking to workouts. TDEE is always higher than BMR.

Which BMR formula does this use?

The default is the Mifflin-St Jeor equation, which is widely used for adults. The calculator also shows the revised Harris-Benedict equation for comparison. The two usually differ by less than about 5%.

Can I raise my BMR?

Muscle uses more energy than fat, so building muscle through strength training can raise BMR slightly. BMR also tends to fall with age and after weight loss.

Should I eat only my BMR in calories?

Generally no. Your BMR does not include any of the energy you use moving around, so eating at or below it is usually much lower than your daily needs. Talk to a healthcare professional before following a very low calorie diet.