BMI and WHO category

BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. In the first example the result is 24.2.

The calculator is not a treatment plan and does not separate muscle from fat. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number.

Input data

Parametry podstawowe modelu

Results

Enter data and click Calculate.

How it works

The calculator uses the numbers you enter. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. In the first example the result is 24.2.

The five form fields are Weight, Height, Waist circumference, Joint pain limiting activity, and Weight-gain prone medicines. BMI means: This is the main result on this page. In the first example it is 24.2. Weight means: The first form field. It enters the formula or sits beside the result. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. Height means: The second form field. The calculator is not a treatment plan and does not separate muscle from fat.

The second example gives 28.4. The third example gives 16.6. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. In the first example the result is 24.2.

The calculator is not a treatment plan and does not separate muscle from fat.

Enter 70, 170, 88, 2, 0, then click Calculate. A comma in 12.5 is read the same way as a period. Fields on a 0-10 scale are notes and are not the primary result unless this page formula says so.

Formula

BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number.

What these numbers mean

In the first example the result is 24.2. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number.

BMI
This is the main result on this page. In the first example it is 24.2.
Weight
The first form field. It enters the formula or sits beside the result. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number.
Height
The second form field. The calculator is not a treatment plan and does not separate muscle from fat.

How to use

  1. Enter Weight 70.
  2. Add Height 170, Waist circumference 88, Joint pain limiting activity 2, Weight-gain prone medicines 0.
  3. Click Calculate. The result is 24.2.
  4. The second example gives 28.4. The third example gives 16.6.
  5. The calculator is not a treatment plan and does not separate muscle from fat.

Examples

Example 1

  • Weight 70
  • Height 170
  • Waist circumference 88
  • Joint pain limiting activity 2
  • Weight-gain prone medicines 0

24.2

BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. In the first example the result is 24.2.

Example 2

  • Weight 92
  • Height 180
  • Waist circumference 102
  • Joint pain limiting activity 4
  • Weight-gain prone medicines 0

28.4

BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. In the second example the result is 28.4.

Example 3

  • Weight 48
  • Height 170
  • Waist circumference 70
  • Joint pain limiting activity 1
  • Weight-gain prone medicines 0

16.6

BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. In the third example the result is 16.6.

Related calculators

Common questions

What does 24.2 mean?

In the first example the result is 24.2. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number.

What is the second example?

With the second set of fields the result is 28.4.

What is the third example?

With the third set of fields the result is 16.6.

How is the result calculated?

BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number.

What does the calculator not do?

The calculator is not a treatment plan and does not separate muscle from fat.

What do BMI, Weight ({{mass}}), and Height ({{height}}) mean?

This is the main result on this page. In the first example it is 24.2. The first form field. It enters the formula or sits beside the result. BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. The second form field. The calculator is not a treatment plan and does not separate muscle from fat.

Does a comma in 12.5 work?

Yes. 12.5 and 12,5 are read the same way.

Are 0-10 fields the primary result?

No. Fields on a 0-10 scale are notes, unless this page formula counts marked items from them. The primary result comes from this page formula.

How is BMI calculated?

Mass divided by height squared. The result also shows the adult WHO category. Waist sits beside that number.

What WHO categories does this page use?

Below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. That is a screening convention, not a treatment plan.

Does BMI separate muscle from fat?

No. The calculator is not a treatment plan and does not weigh body composition.

Which units for mass and height?

Kilograms and centimetres in metric, or pounds and inches in US, following the header.

Does waist change BMI?

No. Waist sits beside mass / height squared.

Sources

BMI is mass divided by height squared. The result also shows the adult WHO category: below 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, from 30 obesity. Waist sits beside that number. The calculator is not a treatment plan and does not separate muscle from fat.

Page updated in 2026.