BodyCalStart with your maintenance calories
Before you can lose weight, you need to know how many calories your body burns in a normal day — your Total Daily Energy Expenditure (TDEE). TDEE combines your basal metabolic rate (the energy your body uses just to stay alive) with the calories you burn through movement, exercise, and digestion.
The most accurate everyday method is the Mifflin–St Jeor equation, which estimates your BMR from your age, sex, height, and weight, then multiplies it by an activity factor. For most adults this lands between 1,600 and 3,000 kcal per day. Our calorie deficit calculator runs this math for you in seconds.
Choose a sustainable deficit
Weight loss happens when you consistently eat fewer calories than you burn. A deficit of 500 kcal per day yields roughly 0.45 kg (1 lb) of fat loss per week; 1,000 kcal per day yields roughly double that. Larger deficits work faster on paper but are dramatically harder to sustain, increase muscle loss, and raise the risk of rebound weight gain.
For most people, a deficit of 15–25% of TDEE is the sweet spot — fast enough to see progress within weeks, gentle enough to maintain energy, training quality, and sanity.
Don't go below the safety floor
Most clinical guidance recommends not dropping below 1,200 kcal/day for women or 1,500 kcal/day for men without medical supervision. Below these levels it becomes very difficult to meet protein, vitamin, and mineral needs, and metabolic adaptation accelerates.
If the deficit you want pushes you under these floors, slow your target rate instead. Losing 0.5 kg per week for six months beats losing 1 kg per week for three weeks and quitting.
Track, adjust, repeat
Calculators give you an excellent starting estimate, but every body is different. Weigh yourself a few times per week, average the results, and compare your real rate of loss to your plan after 3–4 weeks. If you're losing slower than expected, trim 100–200 kcal; if faster than planned (or you feel terrible), add some back.
Treat your calorie target as a living number, not a contract. The people who succeed long-term are the ones who adjust calmly instead of restarting dramatically.