About this tool
This free BMI calculator works out your Body Mass Index from your height and weight — in metric (cm / kg) or imperial (ft-in / lb) units — and shows which weight category you fall into.
BMI is a quick screening figure; it doesn't account for muscle, build or body composition, so treat it as a general guide, not medical advice.
How BMI categories work
- Under 18.5 — Underweight
- 18.5 – 24.9 — Normal weight
- 25 – 29.9 — Overweight
- 30 and over — Obese
How to use it
- Pick your units — metric or imperial
- Enter your height and weight
- Read your result — your BMI value and category update instantly