Health Calculators

Calculate how many liters of water you need per day based on your weight and physical activity. Results in milliliters and equivalent glasses.

Estimate your ideal body weight from your height and sex using the Devine, Robinson, Miller, and Hamwi formulas, plus the healthy weight range for a normal BMI (18.5–24.9).

Estimate your body fat percentage with the U.S. Navy tape method using just your height, neck, waist, and hip. See your fat mass, lean mass, and fitness category by sex.

Calculate your basal metabolic rate (BMR) with the Mifflin-St Jeor equation and see your total daily calorie expenditure (TDEE) for five activity levels. Free, instant, and accurate.

Estimate your ovulation day and fertile window from the first day of your last period and your cycle length. See your most fertile days and when your next period is likely to start.

Split your daily calories into grams of protein, carbs, and fat based on the percentages you choose. Instant macronutrient breakdown using 4 kcal/g for protein and carbs and 9 kcal/g for fat.

Calculate your running pace in minutes per kilometre and per mile, plus your speed in km/h, from the distance and total time of your run. Perfect for planning 5K, 10K, half and full marathon efforts.

Calculate your maximum heart rate and the 5 training zones from your age. Estimate the beats-per-minute ranges for recovery, aerobic, threshold, and maximum effort.

Estimate your one-rep max (1RM) from the weight and reps you lifted using the Epley formula, plus a full table of training percentages.

Find out what time to go to bed or wake up based on 90-minute sleep cycles. Waking up between cycles helps you feel more rested.

Convert your dog's or cat's age into human years. Based on the modern equivalence, not the old '7 years per year' myth. Instant, free and accurate.

Estimate how many calories you burn during exercise based on the activity, your weight, and the duration. Uses the MET × weight (kg) × hours formula.

Calculate your waist-to-height ratio (WHtR), a simple indicator of cardiometabolic risk. A value below 0.5 is generally considered healthy.

Calculate how much protein you need per day based on your weight and activity level, from sedentary (0.8 g/kg) to athletes and muscle gain (2.0 g/kg).

Pick your fasting method and the time of your last meal, and find out exactly when you can eat again and how long your eating window lasts.

Predict your next period, estimated ovulation day and fertile window. Enter the first day of your last period, your cycle length and period length to see your upcoming dates instantly.

Estimate your blood alcohol content (BAC) with the Widmark formula. Enter your weight, sex, drink volume, alcohol strength and time to get a rough BAC in g/L and percent.

Find out how much smoking really costs you. Enter cigarettes per day, pack size and price and see your daily, weekly, monthly, yearly and 10-year spend instantly.

Calculate your body surface area (BSA) in m² using the Mosteller and Du Bois formulas. Enter your weight and height to get both results instantly, side by side.

Find out how many weeks and days pregnant you are from your last menstrual period or conception date. See your gestational age, trimester, due date, days remaining, and pregnancy progress.

Work out your baby’s weight and height percentiles using the WHO growth standards (0 to 60 months). Fast, free, for boys and girls.