Basal Metabolic Rate (BMR) Calculator
Calculate your Basal Metabolic Rate with the Mifflin-St Jeor equation — the calories your body burns at complete rest — and scale it to your activity level.
Your Basal Metabolic Rate is the energy your body spends just staying alive: breathing, circulating blood, repairing cells — before you take a single step. The standard estimate uses the Mifflin-St Jeor equation, which factors in sex, weight, height, and age, and is what most dietitians start from.
Enter your stats to see your BMR, then multiply by your activity level to estimate total daily energy needs (TDEE). Eating below TDEE produces a deficit; eating above it, a surplus. Everything runs locally — your measurements are not sent anywhere.
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BMR Calculator
Basal Metabolic Rate across three evidence-based formulas, with total daily calories — 100% private.
All BMR formulas are statistical estimates and vary by body composition and genetics. Use the value as a starting point for planning — not as medical or dietary advice. Consult a professional for personalized guidance.
Three formulas, one number you can act on
BMR (basal metabolic rate) is the calories your body burns at complete rest — just keeping you alive. Multiplying it by an activity factor gives your daily maintenance calories. The three formulas differ mainly in how they weigh muscle vs. overall mass.
Women: 10×kg + 6.25×cm − 5×age − 161
The best-supported formula for the general population; it is what most dietitians and modern apps use by default.
Women: 447.593 + 9.247×kg + 3.098×cm − 4.330×age
The older classic; tends to run slightly higher than Mifflin for most people.
The most accurate when you know your body-fat %. It uses lean mass directly, so athletes typically see higher values. Enter a body-fat % in the calculator to enable it.
| Activity level | Factor | Daily calories |
|---|---|---|
| Sedentary | × 1.2 | 1,644 kcal |
| Lightly active | × 1.375 | 1,884 kcal |
| Moderately active | × 1.55 | 2,124 kcal |
| Very active | × 1.725 | 2,363 kcal |
| Extra active | × 1.9 | 2,603 kcal |
Maintenance = BMR × factor. Eat less to lose, more to gain — adjust in small (~200 kcal) steps.
Sample person: female, 30, 165 cm, 65 kg, ~24% body fat.
- Mifflin-St Jeor:10×65 + 6.25×165 − 5×30 − 161 = 1,385 kcal/day
- Harris-Benedict:447.593 + 9.247×65 + 3.098×165 − 4.330×30 ≈ 1,395 kcal/day
- Katch-McArdle:LBM = 65 × 0.76 = 49.4 → 370 + 21.6×49.4 ≈ 1,437 kcal/day
- Moderately active:1,385 × 1.55 ≈ 2,147 kcal/day to maintain weight
About this basal metabolic rate calculator
This page covers bmr formula, how many calories do i burn at rest, tdee calculator, mifflin st jeor equation — all the same underlying task as basal metabolic rate calculator. The tool above is FreeToolHub's bmr calculator embedded in full: every feature works right here, and nothing you process is uploaded to any server.
Frequently asked questions
What is a normal BMR?
For most adults it lands between roughly 1,200 and 1,800 calories per day — women at the lower end, men at the higher end, declining slowly with age. A 30-year-old woman at 65 kg and 165 cm estimates to about 1,340 kcal; a comparable man estimates to about 1,580 kcal.
How is BMR different from TDEE?
BMR is rest-only. Total Daily Energy Expenditure multiplies BMR by an activity factor — about 1.2 for sedentary work up to roughly 1.7–1.9 for heavy physical labor or daily training. Weight planning should always use TDEE, because eating at BMR level while active means a steep deficit.