BMR Calculator: Basal Metabolic Rate
Find the calories your body burns at complete rest using the Mifflin-St Jeor equation, the modern gold standard for BMR estimation.
Your BMR
- Per hour
- 74 kcal
- Per minute
- 1.24 kcal
- × 1.2 (sedentary)
- 2,139 kcal
- × 1.55 (moderate)
- 2,763 kcal
Worked examples
How BMR is calculated
BMR is the energy your body needs to keep the lights on when you do nothing at all. Heart pumping, lungs breathing, kidneys filtering, brain running, body temperature regulating, that's BMR. The Mifflin-St Jeor equation, published in 1990, is the modern standard and is what this calculator uses:
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Mifflin-St Jeor outperforms the older Harris-Benedict equation (1919) and the Katch-McArdle equation (which requires accurate body fat). It is within about ±10% of an actual lab measurement for most people.
How to use your BMR
BMR by itself isn't a calorie target, it's an ingredient. Multiply it by an activity factor to get TDEE (your total daily burn) and use that for setting fat-loss, maintenance or muscle-gain calories. Activity multipliers we use:
- Sedentary: 1.2
- Light (1-3 sessions/wk): 1.375
- Moderate (3-5 sessions/wk): 1.55
- Active (6-7 sessions/wk): 1.725
- Athlete (2x/day): 1.9
Two healthy adults at the same weight can have BMRs that differ by 10-15% based on how much lean mass each carries. That's normal, don't compare yours to your sibling's and panic.
Worked examples
Example 1. 35F, 163 cm, 60 kg. BMR = 10×60 + 6.25×163 − 5×35 − 161 = 600 + 1018.75 − 175 − 161 ≈ 1,283 kcal/day.
Example 2. 40M, 180 cm, 90 kg. BMR = 10×90 + 6.25×180 − 5×40 + 5 = 900 + 1125 − 200 + 5 ≈ 1,830 kcal/day.
Example 3. 22M, 175 cm, 70 kg. BMR = 700 + 1094 − 110 + 5 ≈ 1,689 kcal/day. Young, active and lean, TDEE for a college lifter who walks between classes runs over 2,700.
Common mistakes
- Eating only your BMR. That's a 600-1,000 kcal daily deficit for most adults, too aggressive long term.
- Treating BMR as a precise number. The equation has a confidence interval. Use it as a starting line, not gospel.
- Ignoring it as you lose weight. A 30 lb weight loss can reduce BMR by 150-250 kcal.
- Mixing up BMR and TDEE. BMR is rest only. TDEE includes activity. Don't subtract a deficit from BMR.
- Using ancient formulas. Harris-Benedict was a great formula, in 1919. Pre-WWII bodies were different.
FAQ
What is BMR?+
Basal Metabolic Rate is the number of calories your body burns at complete rest just to keep you alive, breathing, circulating blood, repairing cells. For most adults it accounts for 60-70% of daily calorie burn.
Which BMR formula does this use?+
Mifflin-St Jeor (1990). It is the most accurate equation for the general population in head-to-head studies and is the standard used by clinical dietitians.
Is BMR the same as RMR?+
Almost. Resting Metabolic Rate (RMR) is measured after light morning activity rather than total rest, so it usually runs about 10% higher than true BMR. In everyday use the terms are interchangeable.
Can I increase my BMR?+
A little. Adding muscle adds a few calories per day per pound. The big lever for total daily burn is activity, not BMR.
Why does my friend at the same weight have a different BMR?+
Age, height, sex and lean body mass differences. Two 175 lb people can easily differ by 200 kcal at the resting level.
Should I eat at BMR?+
No. BMR is what you'd burn in a coma. Eating only your BMR creates a large, unsustainable deficit. Eat at TDEE or a moderate deficit below it.
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Related guides
- How Many Calories Should I Eat to Lose Weight?A practical answer with the math, the trade-offs of aggressive vs slow deficits, and the calories most people actually need.
- TDEE Explained: How Your Body Burns CaloriesWhat TDEE actually is, the four components that make it up, and why two calculators can give you different numbers.