Health & Fitness Calculators

Check your Body Mass Index in seconds. Enter your height and weight to see your BMI, your WHO weight category and the healthy weight range for your height. Switch between metric and imperial units.

Work out how many calories you need per day from your age, gender, height, weight and activity level. See your BMR, your TDEE and calorie targets for losing or gaining weight — all based on the Mifflin-St Jeor equation.

Find your exact age in years, months and days from your birth date. Enter any target date — today, a past date or a future one — and see how many days and weeks you have been alive. Handles February 29 birthdays correctly.

Work out your Total Daily Energy Expenditure and the protein, carb and fat targets that match your goal. Choose lose, maintain or gain — the calculator adjusts both calories and macro split. Uses the Mifflin-St Jeor equation.

Estimate your body fat percentage using the US Navy method — a tape-measure formula trusted by the military and fitness professionals. Enter a few circumference measurements and see your body fat percentage, fat mass and lean mass.

Estimate your ideal body weight using four classic formulas — Devine, Robinson, Miller and Hamwi — and see the average. Enter your height and gender to get all four results side by side, plus the clinical reference used in medical settings.

Find out how much water you actually need each day — not a generic 8 glasses, but a target based on your body weight, daily exercise and climate. See the result in litres and in 250 ml glasses so it is easy to track.

Work out your five training zones from your age and resting heart rate — using either the simple 220 − age formula or the more personalised Karvonen method. See the bpm range for recovery, fat burn, aerobic, threshold and VO2 max.

Estimate your baby's due date from your last menstrual period or the conception date. See your current week, trimester and the number of days remaining. Based on Naegele's rule — the standard 280-day count used by obstetricians.

Work out the best time to go to bed based on when you need to wake up. The calculator aligns your bedtime with full 90-minute sleep cycles, so you finish a cycle in light sleep instead of waking up groggy in the middle of deep sleep.

Estimate your VO2 max — the best single measure of aerobic fitness — using the Rockport 1-mile walk test. Walk a mile as fast as you can, record your time and heart rate, and see how you compare to age and gender norms.

See how much sleep you have accumulated as a deficit over any period. Enter your target and actual sleep, choose how many days the pattern lasted, and get the total debt, severity level and recovery time.

Predict your next period, ovulation date and fertile window from your last period and average cycle length. See your next three period dates and the current day of your cycle. Based on the standard luteal-phase method used by cycle trackers.

Plan a sustainable weight loss pace. Enter your stats, goal weight and timeframe — the planner returns your daily calorie target and a weekly loss estimate, flagging whether the pace is healthy, too slow or too fast.

Track your pregnancy week by week. Enter your last period or due date and see your current week, trimester, progress percentage and days until birth. Uses the medical convention of counting from the last menstrual period, not conception.