Calorie Calculator (BMR & TDEE)
Enter your age, height, weight and activity level to get your basal metabolic rate and total daily calorie needs — with targets for losing or gaining weight.
How it works
Your basal metabolic rate (BMR) — the energy your body burns at complete rest — is calculated with the Mifflin-St Jeor equation: for men 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women the same with −161 instead of +5. It is the most accurate practical formula in the nutrition literature.
Total daily energy expenditure (TDEE) multiplies BMR by an activity factor: sedentary 1.2 · lightly active 1.375 · moderately active 1.55 · very active 1.725 · athlete 1.9.
To lose weight steadily, aim for 300–500 calories below TDEE (roughly 0.5–1lb a week); to gain, 300–500 above. Imperial entries (stone/lb, ft/in) are converted automatically. The NHS reference intake — 2,500 kcal for men, 2,000 for women — is a population average, not a personal target.
FAQ
How many calories should I eat a day?
It depends on your size, age, sex and activity. A 30-year-old man of 5ft 9in and 12st 8lb with a desk job needs around 2,100 kcal a day; the same man training 3–5 times a week needs about 2,750. The familiar 2,000/2,500 figures on food labels are population averages — compute your own number and adjust based on how your weight actually responds over a few weeks.
What is the difference between BMR and TDEE?
BMR is what your body burns doing nothing — keeping organs running, roughly 1,400–1,900 kcal for most adults. TDEE adds everything else: daily movement, work and exercise, via the activity multiplier. Diet targets should be set against TDEE, not BMR; eating below BMR for long periods is neither necessary nor advisable for most people.
How big a deficit do I need to lose a pound a week?
About 500 kcal a day — a pound of body fat stores roughly 3,500 kcal, so a daily 500-calorie deficit adds up to one pound per week. In practice weight loss is rarely perfectly linear (water weight, adaptation), so treat the arithmetic as a starting point and adjust every few weeks based on real results. The NHS recommends losing no more than 1–2lb a week.