Calorie Calculator

How your calories are worked out

The calculator first finds your basal metabolic rate (BMR): the calories your body uses at complete rest to breathe, pump blood and keep warm. It uses the Mifflin-St Jeor equation, which studies have found to be one of the most reliable formulas for healthy adults:

• Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
• Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

Your BMR is then multiplied by an activity factor to give your total daily energy expenditure (TDEE). This is the number of calories that keeps your weight steady.

Choosing your activity level

• Sedentary (×1.2): desk job and little or no exercise.
• Light (×1.375): light exercise or sport 1 to 3 days a week.
• Moderate (×1.55): moderate exercise 3 to 5 days a week.
• Very active (×1.725): hard exercise 6 to 7 days a week.
• Extra active (×1.9): a physical job, or training twice a day.

Most people overestimate how active they are. If you are unsure, pick the lower level.

Calories to lose or gain weight

A pound of body fat holds roughly 3,500 calories, so eating about 500 calories a day below your TDEE leads to a loss of around 0.5 kg (1 lb) a week. Eating 250 to 500 calories above it supports slow, steady weight gain. Real results vary, because your body adapts as your weight changes, so recheck your numbers every few weeks.

Why some targets say “Not advised”

Eating too little can cause muscle loss, tiredness and missing nutrients. General guidance is not to go below about 1,500 calories a day for men or 1,200 for women unless a doctor is supervising you. When a target would fall below that, the calculator shows “Not advised” instead of a number. A slower goal, or more activity, is the safer route.

These numbers are estimates for healthy adults. They are not suitable during pregnancy or breastfeeding, for children or teens, or for anyone with a medical condition. Speak to a doctor or registered dietitian for personal advice.