Calorie Calculator

About the Calorie Calculator

This calculator estimates the calories you burn in a day and adjusts that figure for your goal. It first works out your basal metabolic rate with the Mifflin-St Jeor equation (10 × kg + 6.25 × cm − 5 × age, +5 for men or −161 for women), multiplies it by the activity factor you pick to get your TDEE, then subtracts 500 kcal if you chose to lose weight or adds 500 if you chose to gain. The maintain, lose and gain figures are shown side by side so you can see the whole range.

The 500 kcal step is a rule of thumb, not a law of physiology — it comes from the rough idea that a sustained daily deficit of that size produces about half a kilo of loss per week. In practice appetite, activity and metabolic adaptation all push back as weight changes, so the real rate usually differs from the arithmetic.

Everything here is an estimate built from population averages. The equation cannot see your body composition, your medical situation, your medication or how honestly you assessed your activity level — and that activity multiplier alone moves the answer by hundreds of calories. Use it as a starting point and adjust based on what actually happens over a few weeks; for anything beyond that, a doctor or dietitian is the right call. See also the BMR calculator and the macro calculator.