Free Health & Fitness Calculators
Know your numbers. Enter your height, weight, age and training stats to instantly find your BMI, body fat, daily calorie needs, macros, one rep max and training zones. Every calculator is free, runs right in your browser, and takes less than a minute.
Body & Weight
Your BMI score and category, plus the healthy weight range for your height.
Estimate your body fat percentage from simple tape measurements.
Your ideal weight range from four trusted medical formulas.
How much water you should drink per day based on your weight and activity.
Calories & Nutrition
The calories your body burns at complete rest, from the Mifflin-St Jeor equation.
Your total daily calorie burn, with targets for losing, maintaining or gaining.
Daily calories to lose, maintain or gain weight at your chosen pace.
Turn your daily calories into protein, carb and fat gram targets for your goal.
Grams of protein per day for your body weight and activity level.
Training & Performance
Your estimated one rep max from four proven formulas, plus training loads.
Pace per mile or kilometer and finish times for common race distances.
Your five training zones with target beats per minute for each.
Why Use These Calculators?
Every training plan, diet and fitness goal starts with numbers. Whether you want to lose 20 pounds, run a faster 5K or finally hit a 225-pound bench press, guessing gets you nowhere — measuring does. Our calculators use the same formulas used by dietitians, coaches and sports scientists: the Mifflin-St Jeor equation for calories, the U.S. Navy method for body fat, and Epley's equation for strength.
Each calculator explains the math in plain English, walks through a complete worked example, and answers the questions people ask most. Every result is instant, private and free — nothing you type ever leaves your browser.