Fitness calculators

Free calculators for how much to eat, based on the Mifflin-St Jeor equation. Results update as you type, and your age, weight and height never leave your browser.

Calorie database: Calories and macros per 100g and per serving for everyday foods.

Now make it stick

Track this target in Calowly.

Set your calorie target in the app and snap your meals. Calo shows how each one fits your day, so the number on this page turns into what you actually eat.

Formula and text last reviewed on 24 September 2026.

This calculator gives general estimates for healthy adults and is not medical advice. If you are pregnant, breastfeeding, or have a medical condition or an eating disorder, talk to a doctor or dietitian before changing how you eat.