BMI Calculator
Calculate your Body Mass Index from height and weight in metric or imperial units, and see which standard category it falls into.
Normal range is a BMI of 18.5–24.9. BMI is a screening figure, not a diagnosis.
About the BMI calculator
Updated June 2026 · 100% client-side — your data never leaves your browser.
Calculate your Body Mass Index from your height and weight, in metric or imperial units, and see which standard category it falls into. BMI is a quick screening figure relating weight to height.
Your measurements are processed in your browser and never uploaded.
Enter height/weight in cm·kg or ft·in·lb.
Shows whether the BMI is underweight, normal, overweight or obese.
Recalculates instantly as you change values.
Health inputs stay in your browser.
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². For imperial units it's 703 × weight (lb) ÷ height (in)². The tool handles the conversion automatically.
What are the BMI categories?
Standard adult ranges: under 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30+ is obese.
Is BMI an accurate measure of health?
BMI is a rough screening tool, not a diagnosis. It doesn't account for muscle mass, body composition, age or sex, so very muscular people may read high. Consult a professional for a full assessment.
Is my data uploaded?
No. BMI is calculated entirely in your browser.