How the BMI formula works
For metric measurements, BMI is weight in kilograms divided by height in metres squared:
BMI = weight (kg) ÷ [height (m) × height (m)]
For US customary measurements, the equivalent calculation is BMI = 703 × weight in pounds ÷ height in inches squared. The calculator converts the values and rounds the displayed result to one decimal place.
How to use the result
- Check that you selected the correct measurement units.
- Enter weight and height carefully; small input errors can change the result.
- Read the reference category as a general screening range, not as a personal health assessment.
- Discuss individual health questions with a qualified healthcare professional.
Frequently asked questions
Is BMI a diagnosis?
No. BMI is a screening measure and does not diagnose a health condition or directly measure body fat.
Can this calculator be used for children?
This page displays general adult reference categories. BMI for children and teens is interpreted differently, using age- and sex-specific growth references, so do not use this adult category table for them.
Does BMI tell me exactly how much body fat I have?
No. BMI uses height and weight only. It does not distinguish fat mass from muscle or provide a direct measurement of body composition.
What should I do if I am concerned about my result?
Use the result as a starting point for questions, not a conclusion. A qualified healthcare professional can consider your overall circumstances and advise you appropriately.
DietDelta provides general educational information. It does not diagnose conditions or provide individualized medical nutrition therapy.
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