What is a healthy BMI?

A BMI between 18.5 and 24.9 is considered the normal, healthy range for most adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese.

Is BMI accurate for everyone?

BMI is a useful general screen but does not measure body fat directly or account for muscle mass, so it can be misleading for athletes, older adults and some ethnic groups.

Does it work for children?

This calculator uses adult categories. Children and teenagers use age- and sex-specific BMI percentiles, so consult a paediatric chart for them.

Health & Fitness

BMI Calculator

Calculate your body mass index (BMI) from height and weight, in metric or imperial units.

Free browser toolRuns in your browserNo sign-up

Weight (kg)Height (cm)

24.2

BMI · Normal weight

Underweight

< 18.5

Normal

18.5 - 24.9

Overweight

25 - 29.9

Obese

30 +

This tool is for general information only and is not medical advice. Talk to a qualified healthcare professional before making health decisions.

About the BMI Calculator

Body Mass Index (BMI) is a quick screening number that relates your weight to your height. This calculator works it out instantly and tells you which category the result falls into.

Enter your details in metric (kg and cm) or imperial (lb and ft/in) units. The tool shows your BMI to one decimal place along with the standard ranges for underweight, normal, overweight and obese.

BMI is a general guide and does not distinguish muscle from fat, so athletes and very muscular people may read high. Everything is calculated in your browser.

Key features

Metric and imperial units
Instant BMI with category
Standard WHO ranges shown
Private, in-browser calculation

How to use

1Choose metric or imperial units.
2Enter your weight and height.
3Read your BMI and its category.

Examples

Adult BMI

Input: 70 kg and 170 cm

Output: BMI 24.2 - Normal weight

BMI is weight in kilograms divided by height in metres squared; it is a screening guide, not a diagnosis.

Frequently asked questions

What is a healthy BMI?: A BMI between 18.5 and 24.9 is considered the normal, healthy range for most adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese.
Is BMI accurate for everyone?: BMI is a useful general screen but does not measure body fat directly or account for muscle mass, so it can be misleading for athletes, older adults and some ethnic groups.
Does it work for children?: This calculator uses adult categories. Children and teenagers use age- and sex-specific BMI percentiles, so consult a paediatric chart for them.

Health GuidesBMI and Calorie Estimates: How to Use Them ResponsiblyRead guide

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