Calorie Calculator

The calories you burn in a day come from three places: the energy your body uses at rest, the energy used to digest food, and the energy of every movement you make. This calculator estimates that total, called your total daily energy expenditure, from your height, weight, age, sex and activity level, then shows the calorie targets for maintaining, losing and gaining weight.

The resting component is the largest, usually 60% to 70% of the total, and it is estimated with the Mifflin-St Jeor equation, which is the formula most dietitians prefer for the general population. Activity is applied as a multiplier ranging from about 1.2 for a sedentary day to 1.9 for heavy physical work or twice-daily training. The multiplier moves the result more than anything else, which is why honest self-assessment matters here.

A commonly used rule is that 3,500 calories equals about one pound of body fat, so a deficit of 500 calories a day is often described as losing a pound a week. In practice the response is not perfectly linear: as you lose weight, your maintenance requirement falls, and adaptations reduce energy expenditure slightly. The estimate is most useful as a starting point that you adjust based on what actually happens over two to three weeks.

The floors matter as much as the target. Very low intakes make it hard to meet protein, micronutrient and fibre needs, and aggressive deficits tend to be abandoned. A moderate deficit of 300 to 500 calories is usually sustainable, and a gain target of a few hundred calories above maintenance supports muscle growth without excessive fat gain. Anyone with a medical condition, or who is pregnant, should treat this as informational only.

This calorie calculator is an educational estimate using the Mifflin-St Jeor equation and a generic activity multiplier. It is not medical or dietary advice and is not appropriate for pregnancy, eating disorders, or clinical conditions. Consult a registered dietitian or physician for personal guidance.