BMI Calculator: Check Your Body Mass Index

Your Measurements

Height

Weight

kilograms

BMI Categories

Underweight

< 18.5

Normal Weight

18.5–24.9

Overweight

25–29.9

Obese

≥ 30

BMI is a simple screening tool, not a diagnostic measure. Athletes with high muscle mass often have elevated BMI without excess body fat.

FAQ

What is a healthy BMI?▾

A BMI between 18.5 and 24.9 is considered healthy for most adults. However, BMI doesn't account for muscle mass or body composition — it's just one screening tool.

Is BMI accurate for athletes?▾

BMI is unreliable for athletes. Muscle weighs more than fat, so muscular individuals often fall in the 'overweight' BMI range despite excellent body composition. Use body fat percentage for a better measure.

What should I do if my BMI is high?▾

A high BMI may suggest excess body fat, but consult a healthcare professional for proper assessment. Combined with regular exercise and a balanced diet, gradual fat loss is the healthiest approach.

TDEE Calculator → Macro Calculator →

How BMI is calculated

Body Mass Index is your weight in kilograms divided by your height in metres squared (kg/m²). In imperial units the same number is 703 × weight in pounds ÷ height in inches squared. The calculator converts your units for you and rounds to one decimal place.

BMI categories for adults

BMI	Category
Below 18.5	Underweight
18.5 – 24.9	Normal weight
25 – 29.9	Overweight
30 and above	Obese

These are the standard adult cut-offs used by the World Health Organization. They are population-level screening ranges, not a diagnosis.

Why BMI can mislead if you lift

BMI only sees height and weight. It cannot tell muscle from fat, so muscular people often land in the "overweight" range despite a low body-fat percentage. It also ignores where weight is carried, age, sex and ethnicity. Waist measurements and body-fat estimates give a fuller picture, and a healthcare professional can interpret your numbers properly.

Who should not rely on BMI

People under 18 (growth charts are used instead)
Pregnant women
Bodybuilders and other very muscular athletes
Older adults, where muscle loss can hide excess body fat

If you want to act on your number, the next step is usually to work out your calorie needs with the TDEE calculator and set protein and fat targets with the macros calculator. For the training side, see our guide to choosing a workout split. Read how this tool is built in our calculator methodology.