Free Health & Fitness Calculators
BMR, TDEE, ideal weight, body fat, macros, heart rate, and more — free health and fitness calculators.
BMR Calculator
Find the calories your body burns at rest.
TDEE Calculator
Find your daily maintenance calories.
Ideal Weight Calculator
Estimate your ideal body weight.
Healthy Weight Calculator
Find the healthy weight range for your height.
Lean Body Mass Calculator
Estimate your lean (fat-free) body mass.
Body Surface Area Calculator
Calculate body surface area (BSA).
Calories Burned Calculator
Estimate calories burned by activity.
One Rep Max Calculator
Estimate your one-rep max from a lift.
Target Heart Rate Calculator
Find your heart-rate training zones.
Protein Calculator
Find your daily protein target.
Carbohydrate Calculator
Find your daily carbohydrate target.
Fat Intake Calculator
Find your daily fat target.
BAC Calculator
Estimate blood alcohol content.
GFR Calculator
Estimate kidney function (eGFR).
Army Body Fat Calculator
Estimate body fat with the Army tape method.
Body Shape Calculator
Find your body shape from measurements.
Pregnancy Weight Gain Calculator
See the recommended pregnancy weight gain.
Pregnancy Calculator
Track your due date and pregnancy week.
Pregnancy Conception Calculator
Estimate the conception date from a due date.
Conception Calculator
Estimate ovulation and the fertile window.
Period Calculator
Predict your next periods and ovulation.
Anorexic BMI Calculator
Check BMI against the anorexic threshold.
Overweight Calculator
See how far you are above a healthy weight.
Weight Watchers Points Calculator
Estimate points from calories, fat, and fiber.
About these 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.