Calculate your BMI online for free with metric or imperial units. Get your body mass index and weight category instantly. Private, no signup required.
First time here? Choose metric or imperial units Your input is processed locally and disappears when you close the tab.
Body Mass Index remains the quickest widely-used screening number for relating weight to height. Our free BMI Calculator computes it instantly in metric (kg/cm) or imperial (lb/ft-in) units, places the result on the standard WHO category scale, and shows the healthy weight range for your specific height.
BMI is weight in kilograms divided by height in meters squared. The WHO bands — underweight below 18.5, normal to 24.9, overweight to 29.9, obese at 30+ — make it useful for tracking trends over time, even though the metric famously can't tell muscle from fat. Athletes and older adults in particular should read it as one data point, not a verdict.
Unlike most BMI sites, this one collects nothing: your height and weight are processed in your browser and never leave your device — no cookies harvesting health data, no email gates. Convert units first with our Unit Converter, or track weight change as a percentage with the Percentage Calculator.
Choose metric or imperial units
Enter your height
Enter your weight
Read your BMI value instantly
See your category and the healthy range for your height
Disclaimer: BMI is a general screening measure and does not account for muscle mass, age, sex, or body composition. It is not a medical diagnosis — consult a healthcare professional for personal advice.