Calorie Calculator

Estimating the energy your body uses each day

Your body burns energy all day, even at rest. This calculator first estimates your basal metabolic rate, the energy needed for breathing, circulation and other basic functions, using the Mifflin-St Jeor equation, which is widely used because it tends to be more accurate than older formulas for most adults. It then multiplies that figure by an activity factor to estimate the total calories you use on a typical day.

The activity level is the setting most people get wrong. Desk jobs with a short evening walk usually belong in the light category, not moderate, even if the workouts feel tiring. Choosing too high a level overestimates your needs and can explain why weight does not change as expected. If you are unsure, start one level lower and adjust after a few weeks based on how your weight actually moves.

The result is an estimate of maintenance calories, the amount at which your weight should stay roughly steady. The calculator also shows gentle adjustments of a few hundred calories above or below that figure for gradual change. Small adjustments are easier to sustain and protect muscle better than aggressive cuts. Everyone's body is different, and factors such as sleep, stress, medical conditions and medicines can affect energy needs. Treat the number as a guide for planning meals rather than a strict target, and focus on the quality of food as well as the quantity. If you are pregnant, managing a health condition, or planning a significant change in weight, speak with a doctor or registered dietitian first.