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BMR Calculatorwithout sign-up
Estimate the calories your body burns at rest. Mifflin-St Jeor, Harris-Benedict or Katch-McArdle, plus daily calories for six activity levels.
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- ƒThree formulasMifflin · Harris · Katch
- ≡Activity tableSix levels, always visible
- ⇄kcal ↔ kJMetric or imperial
BMR Calculator
Enter your details. The preview updates live.
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Units
Sex
Age 15–80
Height 100–250 cm (about 3 ft 3½ in–8 ft 2 in)
Weight 30–300 kg (67–661 lb)
We've assumed Active (×1.55). Pick the row that fits your week.
Daily calories by activity
kcal/dayMaintain
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Lose
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Gain
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Sources National Institutes of Health (NIH) News in Health: about 500 fewer calories a day ≈ 1 lb a week.National Heart, Lung, and Blood Institute (NHLBI): 500–1,000 fewer calories a day for gradual loss.Centers for Disease Control and Prevention (CDC): 1–2 lb a week is more likely to stay off.International Society of Sports Nutrition (ISSN): gaining lean mass needs a calorie surplus.National Strength and Conditioning Association (NSCA): a surplus of about 250–500 calories a day.National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): very-low-calorie diets need a doctor.
Estimates only · starting point · adjust with real-world tracking over 2–3 weeks · not medical advice.
Energy unit
Your daily calories
Enter age, height and weight.
Formula
Clear empties your numbers. Your units, formula and energy unit stay saved on this device.
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Remembers your units, formula and energy unit on this device only.
/bmr-calculator
How it works
Four steps, all in your browser.
- 1
Enter details
Sex, age, height, weight. Metric or imperial.
- 2
Pick a formula
Mifflin-St Jeor is recommended. Katch-McArdle needs body fat %.
- 3
Read your BMR
Calories at rest, updated live.
- 4
Check activity + goals
Six activity rows plus Maintain / Lose / Gain estimates.
Frequently Asked Questions
Answers about BMR Calculator.
Which formula should I use?
Mifflin-St Jeor fits most adults best. Use Katch-McArdle if you know your body fat %. Revised Harris-Benedict is there for comparison.
Why 500 calories less to lose?
Eating about 500 fewer calories a day leads to roughly 0.5 kg (1 lb) of loss a week. US health agencies recommend losing about 0.5–1 kg (1–2 lb) a week; −500 aims at the gentle end, which is easier to keep up. It's a starting point, not a target.
Why +300 to gain?
Building muscle needs a calorie surplus. A small one, about 250–500 a day according to the National Strength and Conditioning Association, limits extra fat. We use +300.
What is TDEE?
Some sites call the Maintain number TDEE (total daily energy expenditure).
Can I switch between kcal and kJ?
Yes. Use Energy unit to switch. 1 kcal = 4.184 kJ, and every number on the page switches together.
Do my numbers leave this device?
No. Everything is worked out in your browser. Only your unit and formula choice are remembered on this device. Your sex, age, height, weight, body fat and activity level are never saved.
Is this medical advice?
No. These are estimates to start from. Adjust them with real-world tracking over 2–3 weeks, and talk to a doctor or dietitian about medical needs.
Related tools
The formulas we use
Mifflin-St Jeor: men 10W + 6.25H − 5A + 5, women 10W + 6.25H − 5A − 161 · Revised Harris-Benedict: men 13.397W + 4.799H − 5.677A + 88.362, women 9.247W + 3.098H − 4.330A + 447.593 · Katch-McArdle: 370 + 21.6 × (1 − F) × W
Activity factors (multiplied by BMR)
1.2 · 1.375 · 1.465 · 1.55 · 1.725 · 1.9
W = weight in kg, H = height in cm, A = age in years, F = body fat as a fraction
Answers about the BMR Calculator.