Health & Fitness calculators
BMI, calorie, body-fat and pregnancy calculators to help you track health and fitness numbers.
BMI Calculator
Free BMI calculator — type in weight and height to get your body mass index and the WHO weight category. Runs in your browser, no sign-up. Metric units (kg, cm).
BMR Calculator
Free BMR (Basal Metabolic Rate) calculator — uses the Mifflin-St Jeor equation, the formula clinical dietitians prefer, with Harris-Benedict as a comparison. Metric units (kg, cm). Runs in your browser.
Body Fat Percentage Calculator (US Navy method)
Free body fat percentage calculator using the US Navy formula — enter height, neck, waist (and hip for women) in metric or imperial, get the % and the category.
Daily Water Intake Calculator
Free daily water intake calculator — estimate how much water to drink each day from your body weight and activity level. Works in your browser.
Heart Rate Zones Calculator
Free max heart rate and training zones calculator. Enter your age (optionally with resting HR for Karvonen) and get the 5 cardio zones in bpm.
Ideal Weight Calculator
Free ideal body weight calculator using the Devine formula — the reference equation in clinical pharmacology. Metric units (kg, cm). Runs in your browser.
Macros Calculator (Protein, Carbs, Fat)
Free macronutrient calculator — split a daily calorie target into grams of protein, carbs and fat by your chosen percentages. Works in your browser.
One Rep Max (1RM) Calculator — Epley, Brzycki & Lombardi
Free one-rep max calculator — enter weight and reps to get your estimated 1RM via Epley, Brzycki, and Lombardi formulas. Unit-agnostic (kg or lb). No sign-up.
Pregnancy Due Date Calculator
Free pregnancy due date and gestational age calculator (Naegele's rule). Type the first day of your last menstrual period and a reference date to see your estimated due date.
Running Pace Calculator
Free running pace calculator — find your pace from a finish time, or predict finish time from a target pace. Works for km and miles. Runs in your browser.
Sleep Cycle Calculator (bedtime & wakeup times)
Free sleep cycle calculator — pick a wakeup time or a bedtime and the calculator returns the best matching times based on 90-minute REM cycles.
TDEE & BMR Calculator
Free TDEE (Total Daily Energy Expenditure) and BMR calculator — uses the Mifflin-St Jeor equation, the formula clinical dietitians prefer. Metric units (kg, cm). Runs in your browser.
Waist-to-Hip Ratio Calculator
Free waist-to-hip ratio (WHR) calculator — check your body fat distribution and health risk using WHO thresholds. Unit-agnostic (works with cm or inches). Runs in your browser.