Calorie Calculator

How the calorie estimate works

The calculator first estimates basal metabolic rate, or BMR, with the Mifflin–St Jeor equation. It uses weight in kilograms, height in centimetres, age and the selected male or female equation. BMR is then multiplied by an activity factor to estimate total daily energy expenditure, often called maintenance calories.

For a weight goal, the tool uses the rough rule that one kilogram of body weight represents about 7,700 kcal. Losing or gaining 0.5 kg per week changes the maintenance estimate by roughly 550 kcal per day. Weight change is not perfectly linear, so this is a planning estimate rather than a guarantee.

Daily targets and macro example

The daily target is your estimated maintenance intake adjusted for the selected goal. The tool does not suggest a loss target below 1,200 kcal per day for the female equation or 1,500 kcal per day for the male equation. If your chosen rate reaches that floor, it shows a warning instead of recommending a lower intake.

The example macro split uses 1.6 grams of protein per kilogram of body weight, 25% of calories from fat and the remaining calories from carbohydrates. It is a simple illustration, not a prescription. Food preferences, culture, training, medication and health conditions can all change an appropriate plan.

Use health information with care

These equations estimate average adult needs. They are not suitable for people under 18, pregnancy, breastfeeding, eating disorders or many medical conditions. If you have diabetes, kidney disease, an eating disorder history, unexplained weight change or another health concern, ask a doctor or registered dietitian for individual advice.