BMI Calculator
Find your Body Mass Index in metric or imperial units, with your category and the healthy range — instantly and privately.
How to use this BMI calculator
- Pick your units. Metric (cm/kg) or imperial (ft/lb).
- Enter height and weight. Use the sliders or type exact values.
- Read your result. Your BMI, category and where you sit on the scale update instantly.
Understanding BMI categories
BMI groups adults into underweight (below 18.5), normal (18.5–24.9), overweight (25–29.9) and obese (30 and above). It's a quick screening tool, not a full health assessment — muscle, age and body type all matter, so use it alongside advice from a health professional.
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². For imperial units we convert pounds and feet/inches to kilograms and metres first. It all runs in your browser.
What is a healthy BMI?
For most adults, 18.5–24.9 is considered normal. Below 18.5 is underweight, 25–29.9 is overweight and 30+ is obese.
Is BMI accurate for everyone?
BMI is a useful general guide but doesn't account for muscle mass, age or body composition. Athletes may read high despite being healthy. Treat it as a starting point, not a diagnosis.
Is my data uploaded?
No. Your height and weight never leave your device — everything is calculated locally in your browser.