Free, no sign-upTDEE calculatorBMR and your daily calorie burn

How BMR and TDEE are calculated

BMR (basal metabolic rate) is how many calories your body burns just to stay alive — breathing, heartbeat, body heat, your organs at work. The calculator uses the Mifflin-St Jeor equation, which reviews found the most accurate of the common equations for healthy adults (more accurate than the older Harris-Benedict):

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

TDEE (total daily energy expenditure) is BMR plus everything else your body does in a day: walking, working, digesting and training. The classic method multiplies BMR by one activity factor: 1.2 for sedentary, 1.375 light, 1.55 moderate, 1.725 active and 1.9 very active.

The problem with one factor: it assumes someone who trains also moves a lot all day. For someone at a desk who trains four times a week it easily adds 300 calories or more that aren't there. So the calculator, like the Fitshare app, works in two parts: daily life — BMR times a modest factor (1.20 to 1.28, and 1.40 for a physical job) — plus the workouts themselves: about 4 calories per kg of bodyweight per session, times sessions per week, spread over seven days. The result shows both methods side by side.

So what do you do with your TDEE? Eat about that much to keep your weight, less to lose — that's the calorie deficit — and a little more to build muscle. The calorie calculator gives the full target, with protein and macros.

Not medical advice. Every formula estimates an average, and real people can be 10% or more off in either direction. To fine-tune it: eat to the number for two or three weeks, track your weight and adjust. If you're pregnant, breastfeeding, have a medical condition or take medication that affects metabolism — with a doctor or dietitian.