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BMI Calculator

Calculate your body mass index from your height and weight, see which WHO category it falls in and the healthy weight range for your height.

Units
cm
kg

Results

Your BMI22.9Normal weight
Healthy weight for your height56.7 kg – 76.3 kg
Room within the normal rangelose 13.3 kg or gain 6.3 kg
Category (WHO adult)
Normal weight
BMI Prime
0.91
Height / weight used
175 cm / 70 kg

BMI is a screening measure for adults. It does not account for muscle mass, age, sex or ethnicity; consult a healthcare professional for an assessment.

How it works

  1. Choose metric or imperial units.
  2. Enter your height.
  3. Enter your weight.
  4. Read your BMI, category and healthy weight range.

Formula

BMI = weight (kg) ÷ height (m)²
BMI = 703 × weight (lb) ÷ height (in)²

Both formulas give the same number; the factor 703 converts imperial units into kg/m².

Example

An adult who is 5 ft 4 in tall and weighs 150 lb.

Inputs

Units
US (ft, in, lb)
Height (feet)
5 ft
Inches
4 in
Weight
150 lb

Result

Your BMI25.7Overweight
Healthy weight for your height107.8 lb – 145.1 lb
To reach BMI 24.9, lose4.9 lb
Load this example into the calculator →

What BMI can and cannot tell you

BMI is a quick, inexpensive way to screen for weight categories that may be linked to health risks. It is used worldwide because it only needs height and weight.

It does not measure body fat directly. Muscular people can have a high BMI without excess fat, and older adults can have a normal BMI with low muscle mass. BMI categories also differ for children and teens, who should use age- and sex-specific percentiles.

Frequently asked questions

What is a healthy BMI?

For adults, the World Health Organization classifies a BMI from 18.5 to 24.9 as a normal (healthy) weight range.

Is BMI accurate for athletes?

Often not. BMI cannot distinguish muscle from fat, so athletes with a lot of muscle may be classed as overweight while being very healthy.

Can children use this BMI calculator?

No. Children and teenagers are assessed with BMI-for-age percentiles, which account for growth. This calculator uses adult categories.

What is BMI Prime?

BMI Prime is your BMI divided by 25, the upper limit of the normal range. A value below 1.0 means you are under that limit.