Health and body calculators
Adult body estimates: BMI, resting and daily energy use, macros, body fat, water intake and the weight for a chosen BMI. Each lesson explains what the estimate cannot tell you.
BMI calculator
Calculate adult body mass index from weight and height, with its WHO adult range and the formula.
Resting energy (BMR) calculator
Estimate adult resting energy in kcal/day with the Mifflin–St Jeor equations. A prediction, not a measurement or intake target.
Body fat estimate calculator
Estimate adult body fat percentage from BMI and age with the Deurenberg regression. A rough population estimate, not a measurement.
Weight at a chosen BMI
Find the weight that matches a BMI you choose at your height. It does not claim an ideal personal weight.
Macro calculator
Turn your own protein, carbohydrate and fat calorie shares into grams per day with 4/4/9 factors. No split is recommended.
Daily energy (TDEE) calculator
Multiply resting energy by a whole-day factor you choose to explore daily expenditure. No diet target is inferred.
Water intake calculator
Turn body weight and a millilitres-per-kilogram factor you choose into litres per day. Not a prescribed drinking target.