Health & Fitness Calculators
Simple numbers help you understand your habits: how many calories you burn, what a healthy weight range looks like, how much water to drink and when to go to bed to wake up between sleep cycles.
Which tool do you need?
Weight and body
BMI Calculator
Calculate your body mass index from height and weight in metric or imperial units and see which adult category it falls in.
Open toolIdeal Weight Calculator
Calculate your ideal weight with the Devine, Robinson, Miller and Hamwi formulas, plus the healthy BMI weight range for your height. In kg and lb.
Open toolBody Fat Calculator
Estimate your body fat percentage with the US Navy tape-measure method. Enter waist, neck, height (and hip for women) to see category, fat mass and lean mass.
Open toolCalorie and BMR Calculator
Estimate your basal metabolic rate with the Mifflin-St Jeor equation, daily calories for your activity level, and calorie targets for losing or gaining weight.
Open toolDaily habits
Water Intake Calculator
Estimate how much water to drink each day from your weight, exercise and climate. See litres, ounces and 250 ml glasses. Free, private, in your browser.
Open toolSleep Calculator
Find the best time to go to bed or wake up using 90-minute sleep cycles. Enter a wake-up time or bedtime and see options with cycles and hours of sleep.
Open toolRunning Pace Calculator
Calculate running pace, finish time or distance. See pace per km and mile, speed, 5K to marathon predictions and a split table. Free and private.
Open toolPregnancy
About these tools
Simple numbers help you understand your habits: how many calories you burn, what a healthy weight range looks like, how much water to drink and when to go to bed to wake up between sleep cycles.
These are estimates for general information, not medical advice. For health decisions, talk to a doctor.
Frequently asked questions
Is BMI accurate?
BMI is a quick screening number based on height and weight. It does not distinguish muscle from fat, so use it as a guide only.
What is BMR?
Basal metabolic rate is the energy your body uses at rest. Calorie calculators multiply it by an activity factor to estimate daily needs.
Is this medical advice?
No. These are general estimates. See a healthcare professional for personal advice.
See all calculators or browse every free tool.