Free Health & Fitness Calculators
BMR, TDEE, ideal weight, body fat, macros, heart rate, and more — free health and fitness calculators.
Health & Fitness Calculators
Free health and fitness calculators for the numbers that guide training and nutrition — BMR and TDEE (maintenance calories), ideal and healthy weight, lean body mass, body-fat percentage (including the US Army tape method), macros (protein, carbs, fat), calories burned by activity, one-rep max, target heart-rate zones, body surface area, eGFR kidney function, BAC, and pregnancy weight gain. Each uses an established medical or fitness formula and runs instantly in your browser with no sign-up.
Frequently asked questions
Are these health calculators free?
Yes — every calculator is free, runs in your browser, and needs no account. They're informational estimates, not medical advice.
Which formulas do you use?
Established ones — Mifflin-St Jeor for BMR/TDEE, Devine for ideal weight, Boer for lean mass, CKD-EPI 2021 for eGFR, Widmark for BAC, and the US Army method for tape body fat.
Should I use these instead of seeing a doctor?
No — they're helpful estimates for planning. For medical decisions, always consult a qualified professional.