Health calculators

Body mass index, calorie needs and healthy weight, using published formulas from WHO and clinical research.

All tools in this category

Pregnancy Due Date CalculatorWork out your due date and how many weeks pregnant you are from the first day of your last period, adjusted for your cycle length. Free and private.
Height ConverterConvert height from feet and inches to centimetres, or from cm to feet and inches, with a full height chart from 4 ft 10 in to 6 ft 6 in.
Weight ConverterConvert body weight between kilograms, pounds and ounces, and stones and pounds, in every direction, with a chart of common weights. Free, instant.
BMI CalculatorCalculate your body mass index (BMI) in metric or imperial units and see the WHO category, including the lower cut-offs WHO suggests for Asian populations.
Calorie CalculatorEstimate how many calories you burn a day (BMR and TDEE) with the Mifflin–St Jeor formula, plus a rough target to lose or gain weight. For adults.
Ideal Weight CalculatorFind the healthy weight range for your height based on WHO BMI ranges, with the Devine and Robinson formulas for comparison. Metric or imperial units.

Estimates, not medical advice

These calculators are for adults aged 18 and over and give general estimates. They don't know your health history; talk to a doctor or dietitian before making changes based on them.