Fitness Calculators Built on Real Science
Transparent formulas, cited sources, no account required. Calculate your daily calorie needs in under a minute.
TDEE Calculator
Total Daily Energy Expenditure: how many calories you burn per day, adjusted for activity level.
Macro Calculator
Protein, carb, and fat targets based on your TDEE and goal: cut, maintain, or bulk.
Calorie Deficit Calculator
Find the right calorie deficit for your weight-loss goal and timeline. Safe rate with lean-mass protection.
BMI Calculator
Body Mass Index with healthy weight range, category, and context on limitations of the metric.
Which calculator should I use first?
Start with the TDEE Calculator. Your Total Daily Energy Expenditure is the foundation for every other number. Once you know how many calories you burn per day, the macro and deficit calculators can give you accurate targets.
If you're trying to lose weight, go to the Calorie Deficit Calculator after you have your TDEE. If you want to optimise protein, carbs, and fat, use the Macro Calculator.
About these calculators
All tools use the Mifflin-St Jeor equation for Basal Metabolic Rate (BMR), published by St Jeor et al. in the Journal of the American Dietetic Association (1990). It is the most validated formula for estimating resting calorie needs in the general population.
Activity multipliers follow the Katch-McArdle convention. Macro ranges use guidance from the Dietary Guidelines for Americans 2020-2025. Every formula is shown on the tool page so you can verify the result yourself.