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Health calculators
that actually help

BMI, calories, body fat, macros, and more — all free, all science-backed, all in one place.

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Body Metrics

Free BMI calculator.

Body Fat Calculator

Estimate your body fat percentage using the US Navy method or BMI method.

Ideal Weight Calculator

Find your ideal weight range based on height and gender using four scientific formulas.

Calculate your lean body mass using three scientific formulas (Boer, James, Hume).

Estimate your blood alcohol content using the Widmark formula.

Calculate your body fat percentage using the official US Army circumference method.

Waist-Hip Ratio

Calculate your waist-to-hip ratio and see your health risk level using WHO standards.

Sleep Calculator

Calculate the best time to go to sleep or wake up based on 90-minute sleep cycles.

Enter your systolic and diastolic blood pressure to instantly see your AHA category, pulse pressure, mean arterial pressure, and what your reading means for your health.

Convert your A1C percentage to estimated average blood glucose (eAG) in mg/dL and mmol/L.

Life Expectancy

Estimate your life expectancy based on lifestyle factors including exercise, diet, smoking, sleep, stress, and social connections.

Find out your biological age based on exercise, diet, sleep, stress, and lifestyle habits.

Calculate your cardiovascular age using blood pressure, smoking status, diabetes, BMI, and activity level.

eGFR Calculator

Calculate your estimated glomerular filtration rate (eGFR) from a serum creatinine blood test.

Calculate your body surface area (BSA) in m² using the DuBois, Mosteller, or Haycock formula.

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Nutrition

Calorie Calculator

Calculate how many calories you should eat per day to lose weight, maintain, or gain muscle based on your age, height, weight, and activity level.

TDEE Calculator

Calculate your total daily energy expenditure.

Macro Calculator

Free macro calculator.

Calculate your basal metabolic rate using three proven formulas.

Protein Calculator

Calculate your ideal daily protein intake based on weight, activity level, and fitness goal — from basic health to muscle building.

Carb Calculator

Calculate your ideal daily carbohydrate intake from keto (5%) to high-carb athlete (65%).

Water Intake Calculator

Calculate your daily water intake based on your weight, activity level, and climate.

Caffeine Calculator

Calculate your total daily caffeine intake from coffee, tea, energy drinks, and more.

Plan your intermittent fasting window.

Calorie Deficit

Calculate the daily calorie target needed to reach your weight goal.

Glycemic Load Calculator

Calculate the glycemic load (GL) of any food.

Calorie Surplus Calculator

Calculate the daily calorie surplus needed to build muscle while minimizing fat gain.

Keto Macro Calculator

Calculate your personalized keto macros — fat, protein, and net carbs — based on your body stats and keto strictness level.

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Fitness

Calories Burned

Calculate how many calories you burn during any activity.

Calculate your one rep max for any lift using three proven formulas.

Heart Rate Calculator

Find your maximum heart rate and all five training zones instantly.

Pace Calculator

Calculate your running pace from distance and time, predict race finish times for 5K to marathon, or convert treadmill speed to pace.

Steps to Calories

Convert your daily step count to calories burned.

VO2 Max Calculator

Estimate your VO2 Max using the 1-Mile Walk Test, 1.

Running Calories

Calculate calories burned running by distance, weight, and pace.

Calculate your maximum heart rate using four validated formulas (Fox, Tanaka, Gellish, Gulati).

Bench Press Calculator

Calculate your estimated bench press 1RM using the Epley formula and see how you compare to strength standards for your bodyweight.

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Pregnancy

Due Date Calculator

Calculate your pregnancy due date from your last period, conception date, or IVF transfer date.

Period Calculator

Predict your next 6 periods, track your cycle phase, and find your fertile window based on your last period date and cycle length.

Ovulation Calculator

Calculate your ovulation date, fertile window, and daily conception probability to maximize chances of pregnancy.

Pregnancy Weight Gain

See how much weight you should gain during pregnancy based on your pre-pregnancy BMI using IOM 2009 guidelines.

All calculators provide estimates for informational purposes only and are not a substitute for professional medical advice. Always consult a healthcare provider before making health decisions.