BMR Calculator
What your body burns at total rest, using the Mifflin-St Jeor equation.
Your BMR (calories burned at total rest)
1721 cal/day
Worked example, step by step
Two reference people, run through exactly the same formulas as the calculator above. Swap in your own numbers and the steps are identical.
Alex
Male · 30 · 5'9" · 170 lb · moderately active
- Weight
- 170 lb × 0.4536
- 77.1 kg
- Height
- 5'9" = 69 in × 2.54
- 175.3 cm
- BMR
- 10 × 77.1 + 6.25 × 175.3 − 5 × 30 + 5
- 1,721 cal
Sam
Female · 30 · 5'5" · 140 lb · lightly active
- Weight
- 140 lb × 0.4536
- 63.5 kg
- Height
- 5'5" = 65 in × 2.54
- 165.1 cm
- BMR
- 10 × 63.5 + 6.25 × 165.1 − 5 × 30 − 161
- 1,356 cal
BMR by weight, at a glance
Weight moves BMR by 10 calories per kilogram (about 4.5 per pound); each year of age costs 5 calories; each centimetre of height adds 6.25. The table holds age at 30 and height at 5'9" (men) and 5'5" (women) and varies only weight, so you can see the slope:
| Weight | BMR, male (5'9") | BMR, female (5'5") |
|---|---|---|
| 120 lb | 1,495 cal | 1,265 cal |
| 140 lb | 1,585 cal | 1,356 cal |
| 160 lb | 1,676 cal | 1,447 cal |
| 180 lb | 1,767 cal | 1,537 cal |
| 200 lb | 1,858 cal | 1,628 cal |
| 220 lb | 1,948 cal | 1,719 cal |
| 240 lb | 2,039 cal | 1,809 cal |
After two weeks: how to adjust
Every number on this page is an estimate of the average person with your stats. You are not the average person, and the only way to find your real number is to eat at the estimate and watch the scale. The rules that make that work:
- Weigh daily, judge weekly. Same scale, same time, after the bathroom, before food. Daily readings swing 2-4 lb on water alone; compare weekly averages, not days.
- Give it 14 days. The first week of any change is mostly water and glycogen. The second week is the first honest read.
- Then move 100-200 calories, not 500. Trending down when you meant to hold? Add 100-200. Trending up? Subtract 100-200. Small moves, then another two weeks.
- Recalculate when your weight changes by 10-15 lb. Your BMR moves with your bodyweight, so a target set months ago is stale.
- Keep protein fixed, flex carbs and fat. Protein is the one macro tied to keeping muscle; it is the last thing to cut and the first to hit.
Common mistakes
- Counting the workout twice. The activity multiplier already includes your training. Adding the calories your watch says you burned on top of it double-counts, often by 300-600 a day.
- Treating the number as exact. Mifflin-St Jeor is accurate to within about 10% for most healthy adults. For Alex that is a 267-calorie band either side of 2,668.
- Eating at BMR. BMR is what you burn asleep and fasting. Eating that little for long is a crash diet with a scientific-sounding name; the deficit belongs under TDEE, not under BMR.
Keep going
- BMR only covers calories burned at total rest; the TDEE calculator adds your real daily activity on top of this number. TDEE Calculator
Frequently Asked Questions
What is BMR?
Basal Metabolic Rate -- the calories your body burns just staying alive at total rest, before any movement, digestion, or exercise is counted.
Which formula does this use?
Mifflin-St Jeor, the equation most commonly recommended over the older Harris-Benedict formula -- it tends to track measured resting energy expenditure more closely in healthy adults.
Is BMR the number I should eat to lose weight?
No -- eating at BMR ignores your actual daily activity and is lower than what most people should eat. Use the TDEE calculator for your real daily number, or the macro calculator for a goal-specific target.
Can I raise my BMR?
Only slowly, and only by adding lean mass: roughly 6 calories a day per pound of muscle, so ten pounds of muscle gained over a year adds about 60 calories to BMR. Nothing you eat or drink changes it meaningfully. The number people can move quickly is TDEE, through activity, not BMR.
Why is a woman's BMR lower at the same weight and height?
The Mifflin-St Jeor equation subtracts 161 for women where it adds 5 for men -- a fixed 166-calorie gap that reflects the average difference in lean mass and organ size at the same bodyweight. Two people of the same sex, weight, height, and age get the same BMR; individual variation around it is about ±10%.
How much does BMR fall with age?
The formula takes 5 calories per year, so 30 to 50 costs 100 calories a day. In practice much of the drop people feel is lost muscle and lower activity rather than age itself, and both are reversible with training. A 50-year-old who lifts can out-burn a 30-year-old who does not.