MMaxTools

Health & Fitness Calculators

BMI, calories, macros, heart rate, running pace and fitness math.

MaxTools' health and fitness calculators turn body measurements and activity numbers into useful answers: your BMI and what it means, the calories you burn at rest and during exercise, how much protein you need, your target heart-rate zones, and the pace math behind your runs.

Every calculator is free, private and runs entirely in your browser — no account, no data upload. Results are educational estimates based on common formulas and population averages; they are not medical advice, so always discuss health decisions with a qualified professional.

All health & fitness calculators

Health

BMI Calculator

Calculate your Body Mass Index and see the healthy weight range for your height.

Health

BMR Calculator

Find your Basal Metabolic Rate — the calories your body burns at rest.

Health

TDEE Calculator

Total Daily Energy Expenditure — the calories you need to maintain your weight.

Health

Macro Calculator

Split your daily calories into protein, carbs and fat targets.

Health

Calorie Deficit Calculator

Plan your daily calorie target and the time to reach your goal weight.

Health

Body Fat Calculator

Estimate body fat percentage from tape measurements — no special equipment.

Health

Ideal Weight Calculator

Ideal body weight by formula plus the healthy BMI range for your height.

Health

Calorie Burn Calculator

Estimate calories burned during running, cycling, gym and 12 more activities.

Health

Water Intake Calculator

How much water should you drink a day? Weight-based hydration target.

Health

Heart Rate Zone Calculator

Find your five training zones from max heart rate — and the Karvonen version.

Health

Running Pace Calculator

Convert pace, speed and finish time for any run distance.

Health

Race Time Predictor

Predict your 5K, 10K, half marathon and marathon times from one result.

Health

Steps to Distance Calculator

Convert steps to kilometers, miles, feet and calories burned.

Health

Sleep Cycle Calculator

Best times to go to bed to wake refreshed — based on 90-minute cycles.

Health

One Rep Max Calculator

Estimate your 1RM from any set — Epley and Brzycki formulas.

Health

VO2 Max Calculator

Estimate VO₂max from a 12-minute Cooper test run.

Health

Waist to Height Ratio Calculator

The 'waist under half your height' rule — a quick central-fat risk check.

Health

Waist to Hip Ratio Calculator

Check body-fat distribution risk with the WHO waist-to-hip guideline.

Health

Lean Body Mass Calculator

Estimate muscle-and-more mass: everything in your body that isn't fat.

Health

BSA Calculator

Body Surface Area from weight and height — Mosteller and Du Bois formulas.

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