BMI Calculator
The BMI Calculator is a free tool that works out your BMI (body mass index) from just your height and weight. BMI uses one worldwide formula — weight (kg) ÷ height (m) ÷ height (m) — and this tool instantly shows your BMI along with your weight category, ideal weight, and a healthy weight range.
Result
Enter your height and weight to see your BMI, category, and ideal weight.
Height and weight calculations run entirely in your browser, and the values you enter are never sent to a server.
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About BMI Calculator
The BMI Calculator is a free tool that works out your BMI (body mass index) from just your height and weight. BMI uses one worldwide formula — weight (kg) ÷ height (m) ÷ height (m) — and this tool instantly shows your BMI along with your weight category, ideal weight, and a healthy weight range.
The cut-offs used to classify weight (underweight, normal, overweight, obese) vary by country and health body. This tool includes the WHO (international), Japan (JASSO), China, Taiwan, and South Korea classifications. It defaults to the standard that matches the page language, and you can switch between them at any time to compare. A color-coded gauge shows at a glance which category your BMI falls into.
Ideal weight is calculated from BMI 22 — the value associated with the lowest risk of disease — as 22 × height (m)². The tool also displays the healthy weight range that falls within the "normal weight" band of the selected standard, so you can use it as a target. You can enter your measurements in metric (cm, kg) or imperial (ft, in, lb).
All height and weight calculations run entirely in your browser, and your values are never sent to a server. No signup or install is required, and you can share your results and inputs through a URL.
How to use
- Choose your units (metric: cm, kg / imperial: ft, in, lb).
- Enter your height and weight to see your BMI and weight category calculated automatically.
- Switch the classification standard (WHO, Japan, China, Taiwan, South Korea) with the selector. The standard matching the page language is selected by default.
- Your BMI, category, ideal weight (BMI 22), and healthy weight range appear in a list, and each row can be copied with one click.
- Click "Share URL" to copy a link that includes your inputs and standard, so you can open the same result on another device or share it with someone.
Use cases
- Anyone who wants a quick BMI and weight check for themselves or family as part of everyday health tracking.
- People on a diet or fitness journey who want to know their target ideal weight and healthy weight range.
- Anyone who wants to know their BMI ahead of a health checkup or screening.
- Comparing how obesity classifications differ by country, such as the WHO international standard versus Japan's.
- Trainers, dietitians, and healthcare workers who need to calculate standard weight from height and weight quickly.
- Anyone who wants to find their BMI from height and weight given in imperial (ft, in, lb) units.
Notes
- The BMI formula — weight (kg) ÷ height (m)² — is the same worldwide. Ideal weight is calculated from BMI 22, the value linked to the lowest disease rate.
- Weight categories differ by country and health body. You can switch between the WHO, Japan, China, Taiwan, and South Korea standards to compare.
- BMI is based on height and weight alone, so it does not account for muscle mass, body fat percentage, age, or sex. Treat the result as a guide only.
- This is an adult metric. Children under 18 are assessed against age- and growth-specific charts, so use this tool's result only as a rough reference for them.
- All calculations run in your browser, and the height and weight you enter are never sent to a server.