Calorie Calculator (TDEE)

Knowing roughly how many calories your body uses in a day is the single most useful number for anyone trying to lose, maintain, or gain weight. This calculator works it out in two steps. First it estimates your BMR — the energy you would burn lying still all day — using the Mifflin-St Jeor equation, the formula most nutrition professionals regard as the most reliable of the common predictive models. Then it multiplies that by an activity factor to give your TDEE, the total calories you actually burn including movement and exercise. From there you get clear targets: eat around your TDEE to hold your weight steady, subtract calories to lose, or add them to gain. A moderate 500-calorie daily deficit corresponds to roughly half a kilogram (about a pound) a week, because a kilogram of body fat stores around 7,700 calories. The tool also breaks each target into protein, carbohydrate, and fat, so you can see what the number means on your plate.

Every calorie formula is a population-level estimate, and no equation can capture your individual metabolism. Two people of the same age, height, and weight can burn noticeably different amounts depending on muscle mass, genetics, hormones, medication, and even how much they fidget. Predictive formulas can be several hundred calories off for any one person. The practical approach is to treat this number as a starting point. Eat around it consistently for two to three weeks, track what actually happens to your weight, and adjust from there — real-world feedback beats any formula. And please remember that this tool is for general education only. It is not nutritional or medical advice, and it is not appropriate for everyone. If you have a health condition, are pregnant or breastfeeding, or are considering a significant change to your diet, speak with a doctor or registered dietitian first.