Calorie Calculator
Estimate how many calories you burn per day, and how many to eat to maintain, lose or gain weight at a given pace. Metric and imperial units are both supported.
Estimates from the Mifflin-St Jeor equation. Track your weight for 2–3 weeks and adjust by 100–200 kcal if the trend is not what you want.
Formula and calculation
Worked example
A 30-year-old man, 180 cm and 80 kg, exercising 3–5 days a week: BMR = 10×80 + 6.25×180 − 5×30 + 5 = 1,780 kcal. With the moderate activity factor 1.55, maintenance is 2,759 kcal/day, and eating 2,259 kcal/day targets about 0.5 kg of loss per week.
Using these numbers in practice
Treat the estimate as a starting point, not a promise. Track your weight for two to three weeks at a given intake — if your weight is trending the way you want, the number is right for you; if not, adjust by 100–200 kcal. Any formula is a population average: two people with identical stats can differ by a few hundred calories in real expenditure. Weight training, for example, adds muscle that burns more at rest, and the estimate lags that change.
What the results mean
- Maintenance calories
- Estimated calories per day to stay at your current weight: your resting metabolism multiplied by your activity level.
- BMR
- Basal metabolic rate — calories your body burns at complete rest, from the Mifflin-St Jeor equation. Everything else is this number scaled by activity.
- Mild weight loss
- Daily intake for losing about 0.25 kg (½ lb) per week — a deficit of 250 kcal/day.
- Weight loss
- Daily intake for losing about 0.5 kg (1 lb) per week — a deficit of 500 kcal/day, the most common target.
- Extreme weight loss
- Daily intake for losing about 1 kg (2 lb) per week — a deficit of 1000 kcal/day. Aggressive; not recommended without medical supervision.
- Mild weight gain
- Daily intake for gaining about 0.25 kg (½ lb) per week — a surplus of 250 kcal/day.
- Weight gain
- Daily intake for gaining about 0.5 kg (1 lb) per week — a surplus of 500 kcal/day.
Frequently asked questions
How many calories should I eat to lose weight?
Start from your maintenance number and subtract 500 kcal/day for roughly 0.5 kg (1 lb) of loss per week. Deficits under 250 kcal/day change the scale slowly enough to be discouraging; deficits over 1000 kcal/day usually backfire through hunger and muscle loss.
Why is my calorie number different from other calculators?
Different equations (Mifflin-St Jeor vs. Harris-Benedict vs. Katch-McArdle) give answers within about 5% of each other, and activity multipliers vary by site. The differences are smaller than the day-to-day error in tracking food, so pick one calculator and stay consistent.
Do I need to eat back the calories I burn exercising?
Your activity level already includes your typical exercise. If you double your training in a given week, add roughly 100–200 kcal/day to the target rather than eating back the raw number a watch reports — wearables overstate calorie burn, often by 20–40%.
Is a very low calorie diet safe?
Diets under about 1,200 kcal/day (women) or 1,500 kcal/day (men) make it hard to get enough protein, vitamins and minerals, and should only be done with medical supervision. The extreme-loss row here is a mathematical point on the scale, not a recommendation.