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BMR calculator

Your basal metabolic rate is usually 60% to 70% of the calories you burn in a day, which is why rest matters more than most workouts.

Updated

How to use it

  1. Step 1Pick your sex and enter your age, height and weight.
  2. Step 2Add your body fat percentage if you know it, to see the Katch-McArdle result.
  3. Step 3Compare the formulas, then turn BMR into a daily target with the TDEE calculator.

Explainer · 0:21

STEP 1 · RESTING BURN BMR (Mifflin-St Jeor) 1,528 kcal/day woman · 35 · 5 ft 6 in · 180 lb STEP 2 · ADD MOVEMENT BMR + everyday activity × 1.375 2,101 kcal/day = TDEE STEP 3 · SET A DEFICIT TDEE minus 500 −500 1,601 kcal/day target STEP 4 · WHAT TO EXPECT 180 lb ~1 lb a week at first slows over time week 0week 30 0:21 · voiced · captions on
Your body burns energy even at rest. That's your BMR: about 1,528 kcal a day for a 35-year-old woman who is 5 ft 6 in and 180 lb.
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How your daily calories are worked out
Read the transcript
  1. Your body burns energy even at rest. That's your BMR: about 1,528 kcal a day for a 35-year-old woman who is 5 ft 6 in and 180 lb.
  2. Daily movement multiplies it. Light activity is × 1.375, so 1,528 becomes about 2,101 kcal. That's your TDEE.
  3. Eat about 500 kcal less than your TDEE and you're in a deficit: around 1,601 kcal a day.
  4. That's roughly 1 lb a week at first. Loss slows as your body adapts, so treat the number as a starting point and adjust.

Three formulas

  • Mifflin-St Jeor (1990): 10 × kg + 6.25 × cm − 5 × age, then +5 for men or −161 for women. The headline number.
  • 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.
  • Katch-McArdle: 370 + 21.6 × lean mass (kg), shown when you enter body fat.

BMR vs TDEE

BMR is energy at complete rest. Your total daily burn adds digestion and movement, so the tool also shows sedentary (× 1.2) and moderately active (× 1.55) totals. For a calorie target, use the TDEE calculator.

Equations estimate an average. A lab test (indirect calorimetry) is the only way to measure your own rate.

Prefer a chart? See Calories by age: precomputed tables for common inputs.

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Common questions

What's the difference between BMR and RMR?

BMR is measured under strict fasting and rest conditions, while resting metabolic rate is measured more loosely. In practice they're within a few percent.

Which BMR formula is most accurate?

Mifflin-St Jeor is usually the best general pick for adults. Katch-McArdle can be closer if you know your body fat accurately.

Does BMR drop when you lose weight?

Yes. A smaller body needs less energy, and the body also adapts a little beyond that.

Can I raise my BMR?

Building muscle raises it modestly. Age, height and sex matter more and can't be changed.

Sources

  1. Mifflin MD et al. A new predictive equation for resting energy expenditure. Am J Clin Nutr 1990
  2. NIDDK Body Weight Planner (NIH)