Calorie deficit calculator
Calorie deficit calculator for weight loss.
EstimateDaily calorie target
Estimate based on the Mifflin-St Jeor equation. Your real needs can be higher or lower; adjust after a few weeks of tracking your weight.
It turns your maintenance calories into a daily calorie target for weight loss at the pace you choose, without going below a safe minimum.
Track this target in Calowly.
Set your calorie target in the app and snap your meals. Calo shows how each one fits your day, so the number on this page turns into what you actually eat.
How it works
First the calculator estimates your TDEE, the calories you burn in a day, from the Mifflin-St Jeor equation and your activity level:
Men: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5
Women: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age − 161
TDEE = BMR × activity factor (1.2 to 1.9)
Daily deficit = weekly loss in kg × 7,700 ÷ 7
Then it subtracts a daily deficit for the pace you pick. A common rule of thumb is that one kilogram of body fat holds about 7,700 kcal (about 3,500 kcal per pound), so the daily deficit is the weekly loss × 7,700 ÷ 7.
It never shows a target below 1,200 kcal a day for women or 1,500 kcal for men. If a pace would go lower, the target is held at that minimum and the calculator shows the slower pace that follows from it.
Example: the same 30-year-old man (80 kg, 180 cm, moderately active) burns about 2,759 kcal a day. Losing 0.5 kg a week takes 0.5 × 7,700 ÷ 7 = 550 kcal a day less, so his target is about 2,209 kcal a day.
Activity levels
| Sedentary | desk job, little or no exercise | × 1.2 |
|---|---|---|
| Lightly active | light exercise 1-3 days a week | × 1.375 |
| Moderately active | moderate exercise 3-5 days a week | × 1.55 |
| Very active | hard exercise 6-7 days a week | × 1.725 |
| Extremely active | physical job plus hard training most days | × 1.9 |
Common questions
How big should my calorie deficit be?
For most people, about 275 to 825 calories a day is a sensible range, which works out to 0.25 to 0.75 kg (roughly 0.5 to 1.5 lb) a week. Smaller deficits are easier to keep up and protect muscle better. Larger ones are best reserved for people with more to lose, ideally with a doctor's guidance.
Why won't the calculator go below 1,200 or 1,500 calories?
Below about 1,200 calories a day for women and 1,500 for men it becomes hard to get enough protein, vitamins and minerals from food, and very low intakes are normally done under medical supervision. So the calculator holds your target at that floor and shows the slower pace instead.
Is 7,700 calories really one kilogram of fat?
It is a useful approximation, about 3,500 calories per pound, but real weight loss is less tidy. The first weeks include water, and as you get lighter your TDEE falls, so progress slows. Treat the time to your goal weight as a rough guide and recalculate every few kilos.
Why am I not losing weight on my calorie target?
The usual reasons are underestimated portions, drinks and snacks that go unlogged, and an activity level set too high. Weigh yourself several times a week and compare two-week averages, since daily numbers jump with water and salt. If the trend stays flat for three weeks, lower your target by 100 to 200 calories.
Should I eat back the calories I burn exercising?
Your activity level already includes your usual exercise, so adding exercise calories on top counts them twice. After an unusually long session, eating back part of it, say half, is a reasonable compromise. Your weight trend over a few weeks is the most reliable sign that the balance is right.
Related calculators
Calorie database: Calories and macros per 100g and per serving for everyday foods.
Sources
Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-7. doi:10.1093/ajcn/51.2.241
Formula and text last reviewed on 24 September 2026.
This calculator gives general estimates for healthy adults and is not medical advice. If you are pregnant, breastfeeding, or have a medical condition or an eating disorder, talk to a doctor or dietitian before changing how you eat.