BMI
Body mass index from weight and height, using the standard WHO categories for adults.
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Body & health calculators
BMI, body-fat percentage, calorie needs, daily water, sleep cycles, reference weight and pregnancy/ovulation dates.
Body fat
Body-fat percentage using the US Navy circumference method — a tape-measure estimate, not a DEXA scan.
Open calculatorCalories
Basal metabolic rate (BMR) from the Mifflin–St Jeor equation and total daily energy expenditure (TDEE) by activity level.
Open calculatorIdeal weight (Devine)
Calculate reference body weight from sex and height using the clinical Devine formula.
Open calculatorDaily water intake
Estimate daily fluid intake in litres from your body weight and minutes of physical activity.
Open calculatorMacronutrients (Protein, Carbs, Fat)
Split your daily calorie target into exact grams of protein, carbohydrates and dietary fat.
Open calculatorWaist-to-hip ratio (WHR)
Calculate your waist-to-hip ratio (WHR) from simple tape-measure readings.
Open calculatorWeight-change timeline
Estimate how many weeks and days it takes to reach your target weight from a daily calorie deficit or surplus (at 7,700 kcal per kg).
Open calculatorSteps to distance & calories
Convert your step count into kilometres walked and estimated calories burned based on height and weight.
Open calculatorSleep cycles
Find optimal wake-up times or bedtimes based on 90-minute sleep cycles plus the time you need to fall asleep.
Open calculatorSleep debt
Calculate how many hours of sleep you are short of your personal target across a run of nights.
Open calculatorCaffeine remaining
Estimate how many milligrams of caffeine remain active in your body after a chosen number of hours.
Open calculatorIntermittent fasting window
Calculate your fasting hours and eating window from the clock times of your last and first meals.
Open calculatorFFMI (Fat-Free Mass Index)
Calculate your lean body mass (LBM) and fat-free mass index (FFMI) from weight, height and body-fat percentage.
Open calculatorDaily protein target
Calculate your daily protein target in grams from body weight and your chosen grams-per-kilogram multiplier.
Open calculatorBody surface area (BSA)
Calculate body surface area (BSA) in square metres from height and weight using the Mosteller formula.
Open calculatorOvulation & fertile window
Estimate your ovulation date, fertile window and potential due date from the first day of your last period and cycle length.
Open calculatorPregnancy & due date
Calculate your estimated due date (EDD), current gestational age in weeks and days, and trimester from your last period.
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