BMI Calculator
Calculate your BMI (Body Mass Index) using your height and weight in metric or imperial units. See your BMI category and what it means.
About the BMI Calculator
Body Mass Index, or BMI, is a ratio of weight to height: your weight in kilograms divided by your height in metres squared. Someone who weighs 70 kg and is 1.75 m tall has a BMI of 70 divided by 3.0625, about 22.9. With pounds and inches, multiply weight in pounds by 703 and divide by height in inches squared. The calculator handles the conversion.
The World Health Organization groups adult BMI into broad ranges: below 18.5 is underweight, 18.5 to 24.9 is a healthy range, 25 to 29.9 is overweight, and 30 or above is obesity. Some health bodies use lower thresholds for people of South and East Asian descent because health risks can appear at lower BMI values.
BMI is a screening tool, not a diagnosis. It cannot tell muscle from fat, does not show where fat is carried, and is not designed for children or pregnancy. Treat the number as one piece of information and speak to a doctor or dietitian for personal advice.
A person who is 1.68 m tall and weighs 64 kg has a height squared of 2.8224. Dividing 64 by 2.8224 gives a BMI of 22.7, which falls in the 18.5 to 24.9 range.
Tips for best results
- Measure height without shoes and weigh yourself at a consistent time of day if you want to track changes.
- Waist measurement and other health markers give context that BMI alone does not.
How to use the BMI Calculator
Why use Toolseza for BMI Calculator?
Use this tool as often as you need with no paywalls, premium tiers, or hidden daily calculation quotas.
All calculations and file manipulations run inside your web browser. Your inputs are never sent to a cloud server.
Results update in real-time as you type or adjust settings, with instant one-click copy and export capabilities.
Works natively on smartphones, tablets, laptops, and desktop computers with zero installation or account creation.
Editorial Standards & Verification: All formulas, algorithms, and conversion factors implemented on Toolseza adhere to openly documented international standards (ISO, NIST, BIPM, W3C). Results are verified against benchmark reference datasets before publication.
Frequently Asked Questions
What is a healthy BMI?
For adults, under 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30+ is obese. BMI is a screening guide, not a diagnostic tool.
How do I calculate BMI manually?
BMI = weight (kg) ÷ height (m)². Imperial: BMI = (weight in lbs × 703) ÷ height in inches².
Is BMI accurate for everyone?
BMI does not distinguish between muscle and fat, so athletes may have a high BMI while being healthy. It is best used as one of several health indicators.