Free, no signup, peer-reviewed
Fitness Calculators
Pick the math you need. All free, all run in your browser, no email required.
TDEE Calculator
Total Daily Energy Expenditure. The total calories your body burns each day. Best starting point for any fat loss or muscle gain plan.
Calculate your TDEE →
BMR Calculator
Basal Metabolic Rate. The calories you burn at complete rest, what your body costs just to stay alive 24/7.
Calculate your BMR →
Macros Calculator
Protein, carbs, and fat targets in grams. Pick your goal (cut / maintain / bulk) and get a science-based macro split.
Calculate your macros →
Maintenance Calorie Calculator
The exact calorie intake that keeps your weight stable. Plus how to adjust to lose or gain at a chosen rate.
Find your maintenance →
Why these formulas?
Every calculator on BurnMath uses peer-reviewed equations from the published nutrition science literature. Mifflin-St Jeor for basal metabolic rate (the most accurate equation for the general population). Katch-McArdle when you provide body fat percentage (more accurate for athletic and lean populations). Standard activity multipliers from FAO/WHO/UN energy expenditure guidelines.
No proprietary "secret formulas." No ads driving the results. The math is documented in plain English on every calculator page so you can see exactly what's being computed.
More calculators coming
Body Fat Calculator (Navy method), Calorie Deficit Calculator (week-by-week planner), One Rep Max Calculator, Ideal Weight Calculator. Bookmark this page.