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.
Frequently asked questions
Are these health calculators free?
Yes — every calculator is free with your account and runs in your browser. 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.