Health & Fitness Calculators

About these calculators

Three estimators cover body measurements and daily energy, and none of them is a substitute for medical advice. BMI Calculator takes weight and height in metric or imperial units and returns a Body Mass Index, rounded to one decimal, with one of four general categories: Underweight, Normal weight, Overweight or Obesity. It uses one set of adult cut-offs for everyone and does not ask for age or sex. Ideal Weight Calculator uses the Devine formula, which starts from a base weight for the sex you choose and adds 2.3 kg for each inch of height above 5 feet, so it only works for heights of 5 feet (152.4 cm) and above.

BMR & Calorie Calculator applies the Mifflin-St Jeor equation, using sex, age, weight in kilograms and height in centimeters, to estimate the calories your body uses at rest. It then multiplies that by the activity level you pick, from sedentary to very heavy training, to estimate total daily calories. All three give estimates from simple formulas. They do not measure body composition, and they cannot account for medical conditions, pregnancy or growth in children. The formulas, their limits and worked examples are explained on each page, and the calculations run in your browser.

Worked examples show how the results read. A person who weighs 70 kg and is 175 cm tall has a BMI of 22.9, which falls in the Normal weight category; 154 lb at 69 inches gives 22.7. For a height of 165 cm the Devine formula gives a reference weight of 56.9 kg (125.5 lb) for a woman, and for 175 cm it gives 70.5 kg (155.3 lb) for a man. A 30-year-old man who weighs 80 kg, is 180 cm tall and picks the moderately active level (a multiplier of 1.55) gets a BMR of 1,780 calories a day and an estimated total of about 2,759. Treat figures like these as a rough starting point to discuss with a doctor or dietitian, not a target.