BMR Calculator
Basal Metabolic Rate — the calories your body burns at rest. Quick uses Mifflin-St Jeor (most accurate). Customize adds Harris-Benedict, Katch-McArdle, Cunningham, Schofield, imperial input, and step-by-step.
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How to use
- 1
Pick your sex — the formulas use different constants for biological sex due to body composition differences.
- 2
Enter age, height, and weight. The result updates instantly.
- 3
Switch to Customize to use imperial units, compare 5 formulas at once, see step-by-step working, and use body-composition-aware formulas (Katch-McArdle, Cunningham) if you know your body fat percentage.
- 4
Multiply by an activity factor to get your daily maintenance calories. The TDEE card does this for you.
Frequently asked questions
BMR is Basal Metabolic Rate — the calories your body burns to stay alive at complete rest. It accounts for the energy to keep your heart beating, lungs breathing, brain functioning, body temperature stable, and cells repairing. For most adults it's 60-75% of daily total energy expenditure.
Mifflin-St Jeor (1990) is the most accurate predictive formula for the general adult population — a 2005 meta-review found it within ±10% of measured BMR for 82% of subjects. Harris-Benedict (1919, revised 1984) over-estimates by 5-8% on average. Katch-McArdle and Cunningham are the most accurate IF you have a reliable body-fat percentage measurement, because they use lean body mass directly. Schofield is WHO-recommended for population-level use.
Both use lean body mass (LBM = weight × (1 − body fat %)). Katch-McArdle: BMR = 370 + 21.6 × LBM. Cunningham: BMR = 500 + 22 × LBM. Cunningham was derived from athletes and tends to predict slightly higher BMR for very lean people. For an average lifter at 15% body fat, the two formulas land within 50-100 kcal of each other.
Schofield (1985) is age-banded — different constants for ages 18-30, 30-60, and 60+. WHO/FAO recommends it for population-level dietary planning. For an individual user it's a useful sanity check but Mifflin is more reliable. Schofield is included in Customize mode for completeness.
BMR is calories at rest. TDEE (Total Daily Energy Expenditure) is BMR plus all the calories you burn from activity — walking, exercise, fidgeting, even chewing. TDEE = BMR × activity factor. A sedentary office worker has TDEE ≈ BMR × 1.2; an athlete TDEE ≈ BMR × 1.9.
No. Eating exactly at BMR is dangerous long-term — your body needs energy for daily activity too. To lose weight safely, eat 300-500 kcal below your TDEE (not BMR), and combine with strength training to preserve muscle. Severe restriction (eating below BMR) slows metabolism and triggers muscle loss.
Two reasons. First, lean body mass (muscle) naturally declines about 3-5% per decade after age 30 — and muscle burns more calories than fat at rest. Second, organ activity slightly decreases. The result: BMR drops about 1-2% per decade. Resistance training in your 40s, 50s, 60s+ slows this dramatically.
Yes. At the same height, age, and weight, men typically have ~10% higher BMR than women due to higher lean body mass and lower body fat percentage. Mifflin-St Jeor, Harris-Benedict, and Schofield all use sex-specific constants. Katch-McArdle and Cunningham use lean body mass directly so the formula is the same for both sexes.
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Source: Mifflin et al. (1990), Frankenfield et al. (2005), Cunningham (1980), Schofield (1985) · Last verified 2026-06. Verify on PubMed. This tool provides estimates only and is not legal, tax or financial advice. Always verify your specific situation with the relevant UAE authority or a licensed advisor before taking action.