Health
Calorie & BMR calculator
Estimate your basal metabolic rate (calories burned at complete rest) and total daily energy expenditure based on age, sex, weight, height, and activity level. Use the result as a starting point for weight maintenance or loss targets.
Formula
Your body burns calories continuously, even at rest, to keep cells alive, the heart beating, and the brain ticking over. That baseline is your Basal Metabolic Rate (BMR). Multiply BMR by an activity factor and you get your Total Daily Energy Expenditure (TDEE) — the calories you need to eat to maintain your current weight.
This calculator uses the Mifflin–St Jeor equation (1990), which the Academy of Nutrition and Dietetics considers the most accurate predictive formula for healthy adults. Activity factors come from the Institute of Medicine. Real metabolism varies ±10–15% from prediction due to muscle mass, genetics, thyroid function, and prior dieting history.
For weight loss, a deficit of 500 kcal/day yields ~0.5 kg (~1 lb) per week — the rate generally considered safe and sustainable. Going lower than 1200 kcal/day for women or 1500 kcal/day for men risks muscle loss and metabolic slowdown.
Examples
- 0130-year-old man, 178 cm, 75 kg, moderately active→ BMR = 10·75 + 6.25·178 − 5·30 + 5 = 1717 kcal · TDEE = 1717 × 1.55 ≈ 2661 kcal/day
- 0235-year-old woman, 165 cm, 60 kg, lightly active→ BMR = 10·60 + 6.25·165 − 5·35 − 161 = 1295 kcal · TDEE ≈ 1781 kcal/day
- 03Same man wanting to lose 0.5 kg/week→ Target 2661 − 500 = 2161 kcal/day (or 2661 calories with ~500 kcal exercise)
FAQ
- Mifflin–St Jeor (1990) is more accurate by about 5% for modern populations and is the formula used by registered dietitians. The older Harris–Benedict equation (1919) tends to overestimate. The differences are within the natural ±10% variance between individuals.