BMR Calculator

Calculate your Basal Metabolic Rate and daily calorie needs

Jump to the next useful tool without leaving your flow.

See more

About this tool

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest just to maintain basic functions like breathing and circulation. This calculator uses the Mifflin-St Jeor formula (a widely-used, accurate estimation method) to calculate your BMR from your age, sex, height, and weight.

How to use this tool

  1. Enter age, sex, height, and weightProvide accurate body inputs for a reliable resting-calorie baseline.
  2. Calculate BMRApply Mifflin-St Jeor equation to estimate calories burned at rest.
  3. Interpret resultUse BMR as base value before adding activity multipliers.
  4. Plan calorie targetAdjust intake for maintenance, fat loss, or muscle gain goals.

How to calculate BMR with the Mifflin-St Jeor equation

For men: BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5. For women the last step is -161 instead of +5. A 30-year-old woman who weighs 65 kg and is 165 cm tall has a BMR of 650 + 1,031 - 150 - 161 = about 1,370 calories a day.

That is the energy used lying still all day. To estimate the calories you actually burn, multiply BMR by an activity factor - from about 1.2 if you sit most of the day to about 1.9 for a physical job - which is what the calorie (TDEE) calculator does.

Key features

  • Gives a practical baseline for nutrition planning.
  • Uses widely accepted modern BMR estimation formula.
  • Helps avoid guesswork in calorie target setting.
  • Useful starting point for fitness and weight programs.

Common uses

  • Setting daily calorie intake for fat loss.
  • Estimating maintenance calories before workout planning.
  • Adjusting meal plans after bodyweight changes.
  • Coaching clients with objective baseline metrics.

Tips for better results

  • Update inputs periodically as weight/composition changes.
  • Pair BMR with realistic activity factor for TDEE estimate.
  • Use consistent measurement units to avoid conversion errors.
  • Treat BMR as estimate and validate with real progress data.

Mistakes to avoid

  • Using BMR directly as daily intake for active lifestyles.
  • Entering inaccurate height/weight values from memory.
  • Ignoring metabolic adaptation during prolonged dieting.
  • Expecting exact calorie precision from formula-only estimates.

Frequently asked questions

It's the foundation for calculating your total daily calorie needs - combined with your activity level, BMR helps estimate how many calories you actually burn in a day, which is useful for weight management planning.

Mifflin-St Jeor is widely regarded by nutrition professionals as one of the more accurate BMR estimation formulas compared to older equations, which is why it's commonly used in modern calculators.

No - BMR is your calorie burn at complete rest. Your actual daily calorie needs (and any target for weight loss/gain) also depends on your activity level on top of BMR.

Multiply BMR by an activity factor: about 1.2 if you mostly sit, 1.375 for light exercise, 1.55 for moderate exercise most days and 1.725 for hard daily training. The result is your total daily energy expenditure (TDEE) - the calories that keep your weight stable.

Mostly because muscle mass tends to decline over the years, and muscle burns more energy at rest than fat. Strength training helps keep muscle, which is why it slows that decline.

For most people it lands within about 10% of a measured value, but very muscular people and people with high body fat can be further off. If you know your body fat percentage, a lean-mass formula such as Katch-McArdle can be closer.