Calorie Calculator (BMR & TDEE)
Estimate the calories your body burns at rest (BMR) and across a full day (TDEE) using the Mifflin-St Jeor equation. You also get rough targets for losing or gaining weight.
How this calculation works
BMR uses Mifflin-St Jeor: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for men, and − 161 instead of + 5 for women.
TDEE multiplies BMR by an activity factor from 1.2 (sedentary) up to 1.9 (very active) to include daily movement and exercise.
The weight-change targets add or subtract 500 calories per day, roughly a 0.45 kg (1 lb) change per week.
Worked example
BMR, TDEE and where calories go
Your body spends energy in four ways. BMR (basal metabolic rate) is the ~60–70% you burn at complete rest to stay alive. TEF (thermic effect of food) is the ~10% used to digest meals. NEAT is everyday movement — walking, fidgeting, chores. EAT is deliberate exercise. Add them and you get TDEE, your total daily energy expenditure.
Activity multipliers
TDEE = BMR × an activity factor:
| Level | Factor | Rough meaning |
|---|---|---|
| Sedentary | 1.2 | Desk job, little exercise |
| Light | 1.375 | Light exercise 1–3 days/week |
| Moderate | 1.55 | Exercise 3–5 days/week |
| Active | 1.725 | Hard exercise 6–7 days/week |
| Very active | 1.9 | Physical job or twice-daily training |
Safe rates of weight change
A deficit of about 500 calories a day loses roughly 0.45 kg (1 lb) a week — a sustainable pace. Very aggressive deficits are hard to maintain and can cost muscle. As a floor, many guidelines advise not eating below about 1,200 kcal (women) or 1,500 kcal (men) without supervision.
Macronutrients matter, not just calories
Calories set weight direction, but the split shapes results. Protein provides 4 kcal per gram and preserves muscle in a deficit; carbohydrates 4 kcal per gram fuel activity; fat 9 kcal per gram supports hormones. A common starting point is protein around 1.6–2.2 g per kg of body weight.