Free, no sign-upCalorie calculatorHow many calories a day?

How the calorie calculator works

Step 1: burn at rest (BMR). The calculator uses the Mifflin-St Jeor equation, found to be the most accurate of the common equations for healthy adults. It estimates how many calories your body burns just to stay alive — breathing, heartbeat, body heat:

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

Step 2: what you burn in a day (TDEE). Most calculators multiply BMR by one activity factor (1.55 for training 3-5 times a week). The problem: that factor assumes you also move all day, and for someone at a desk who trains four times a week it easily adds 300 calories that aren't there. So we calculate it 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.

Step 3: the daily target, by goal:

• Losing weight: 10%, 20% or 25% below your TDEE, depending on the pace you pick, with a deficit of at most 900 calories a day. The target never drops below a safe minimum: 1,200 calories for women, 1,500 for men, and sometimes more for people who train — so that after training, your body still has enough energy left to function.
• Maintaining: the target is your TDEE itself.
• Building muscle: a 12% surplus over your TDEE, and at least 250 calories — a moderate pace aimed at muscle rather than fat.
• Under 18: the calculator shows a maintenance target only. A body that's still growing needs a personal plan from a sports dietitian or a family doctor.

Step 4: protein and macros. Protein: 1.8 g per kg of bodyweight, the usual amount for strength training. Above 90 kg each extra kg counts as half, because most extra weight isn't muscle, up to 220 g a day. Fat: 0.9 g per kg. Everything else is carbs.

Not medical advice. Every formula estimates an average, and real people can be 10% or more off in either direction. The target is a starting point: track your weight for two or three weeks and adjust. If you're pregnant, breastfeeding, have a medical condition, take medication that affects weight or have a history of disordered eating, set the target with a doctor or dietitian.

You have a target. Now you count

A calorie target only works when you know how much you actually ate. Most people stop counting calories after a week or two, because weighing and typing every ingredient takes longer than the meal.

In Fitshare you log a meal in a sentence, a voice note or a photo of the plate, and the AI estimates calories, protein, carbs and fat against your daily target. For gram-level precision there's also the Israeli Ministry of Health food database. More about the nutrition tracker.