Calorie Calculator

A deficit of about 500 calories a day below your maintenance level generally produces around 0.5 kg (1 lb) of weight loss per week. This calculator works out your personal maintenance level first, then subtracts the deficit that matches the rate you select, so the target is scaled to your own body rather than a generic number.

Not very, in absolute terms. The Mifflin-St Jeor equation predicts measured resting metabolic rate to within about 10% for most people, but it can be off by 20% or more for individuals with unusual body composition, and the activity multipliers are broad categories rather than measurements. Treat the result as a starting point, track your actual weight over two to three weeks, and adjust from there.

BMR is the energy your body burns at complete rest just to stay alive. TDEE, or total daily energy expenditure, is your BMR multiplied by an activity factor that accounts for movement, exercise and digestion. Maintenance calories and TDEE are the same thing — the intake at which your weight stays roughly stable.

Very low intakes are not appropriate for most adults without medical supervision, and this tool flags targets that fall below roughly 1,200 kcal for women and 1,500 kcal for men. Aggressive deficits tend to cost you muscle and are harder to sustain than a moderate one. Speak to a healthcare professional before going that low.

It is the conventional estimate for the energy stored in a kilogram of body fat, which works out to about 3,500 calories per pound. It is a rule of thumb, not a physical constant — real weight change also includes water, glycogen and lean tissue, so week-to-week readings on the scale will not track it exactly.

Yes. Every calculation runs in JavaScript inside your browser. Nothing you type is transmitted to a server, logged or stored, so your height, weight and age stay on your device.