BMI calculator

Body mass index from your height and weight.

How it's calculated

BMI = weight (kg) ÷ height (m)². Categories: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30 and over obese.

It's a screening tool: it can't tell muscle from fat, so muscular people may read high.

Guides

How accurate is BMI?

It's a quick screening tool, not a diagnosis. It can't tell muscle from fat, so very muscular people may read high.

BMI or body fat percentage — which is better?

Body fat percentage. BMI uses only height and weight, so it can stay flat while you swap fat for muscle.

How many calories do I need a day?

Your BMR multiplied by an activity factor. The Calorie calculator does this and adjusts for your goal.

How fast is it safe to lose weight?

About 0.5–1 kg (1–2 lb) a week. Faster loss tends to cost muscle and slow your metabolism.