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Result
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Formula
BMI = weight (kg) / (height (m) × height (m))
Example
70 kg and 1.75 m gives BMI ≈ 22.86
What is the BMI formula on this page?
BMI = weight (kg) ÷ (height in metres × height in metres). A person who is 70 kg and 175 cm has a height of 1.75 m, so BMI is 70 ÷ (1.75 × 1.75), about 22.86, which this page labels Normal.
The bands match the cut points written in the calculator: 18.5, 25 and 30. They are the adult screening cut points commonly published by the World Health Organization. They are not a personal medical classification.
BMI does not measure body fat, muscle, bone, or where weight sits on the body. Two people with the same BMI can have different health profiles.
When should you not rely on this BMI estimate?
Do not use it as a diagnosis, a training plan, or a reason to change food or medicine. Athletes, older adults, children, and people who are pregnant need a different reading than a single adult cut point.
If a clinician has asked for height and weight, take the measured values to them. This page only shows the arithmetic and the band those cut points produce.
How to use this calculator
- Enter weight in kilograms. Use kilograms. A weight in pounds will not match this formula.
- Enter height in centimetres. The page divides by 100 to get metres before it squares the height.
- Read the BMI and the band. The result is the number and one of the four labels above. It is a screening estimate, not a diagnosis.
Questions about BMI Calculator
Does this BMI calculator use pounds or feet?
No. Weight must be in kilograms and height in centimetres. Convert first, or use the unit converter for a single conversion and then come back.
Why is 24.9 called Normal and 25 called Overweight?
The page uses a cut at 25. A value from 18.5 up to, but not including, 25 is labelled Normal. A value from 25 up to, but not including, 30 is labelled Overweight.
Is BMI the same as body-fat percentage?
No. BMI is a ratio of weight to height. It does not measure fat, muscle, or fitness.
Can I use this result for a child?
No. These adult cut points are not a child growth chart. Ask a clinician for an age-specific chart.
Read the guide
The BMI page divides weight in kilograms by height in metres squared. Height is entered in centimetres and divided by 100. Below 18.5 is labelled Underweight, 18.5 up to 25 is Normal, 25 up to 30 is Overweight, and 30 or above is Obese. Those words are screening bands, not a diagnosis.
Open “How to read the BMI number on this site”What this helps you do
- Estimate BMI from the inputs you already have.
- Check the result against the formula and the worked example.
- Change one value at a time and compare the new estimate.
Limits to keep in mind
- The figure is only as complete as the inputs on this form.
- Rounding, fees, and local rules can change the real-world number.
- Use it to learn and compare. Confirm important finance or health decisions with a qualified professional.