BMI Calculator
Calculate Body Mass Index with category classification.
Overview
Body Mass Index is computed by dividing weight in kilograms by the square of height in metres. It provides a rough screening category — underweight, normal, overweight, or obese — to help individuals and clinicians identify potential weight-related health risks. Tooler supports both metric and imperial inputs and shows the WHO classification alongside the numeric result.
Common use cases
- Screen for potential weight-related health risks at routine check-ups.
- Track weight management progress over time with consistent measurements.
- Check BMI as a prerequisite for insurance or surgery pre-screening.
- Use alongside other metrics for general fitness goal-setting.
Examples and notes
- A person who is 170 cm tall and weighs 70 kg has a BMI of 24.2 — Normal range.
- At 85 kg and the same height, BMI is 29.4 — Overweight range.
- At 55 kg, BMI drops to 19.0 — still Normal but closer to the lower boundary.
Important note
BMI is a population screening metric, not a clinical diagnosis. It does not account for muscle mass, bone density, age, or body fat distribution. Athletes, elderly adults, children, and pregnant women require additional clinical interpretation.
Frequently Asked Questions
What BMI range is considered healthy?
18.5 to 24.9 is generally classified as normal for adults. Below 18.5 is underweight; 25–29.9 is overweight; 30 and above is obese.
Is BMI a medical diagnosis?
No. BMI is a screening metric, not a clinical diagnosis. It does not account for muscle mass, bone density, or fat distribution.
Why is BMI less accurate for athletes?
Athletes have higher muscle mass which weighs more than fat, so their BMI may appear in the overweight range despite very low body fat percentage.
How do I convert height from feet and inches to cm?
Multiply feet by 30.48 and add inches multiplied by 2.54. For example, 5 feet 10 inches = 177.8 cm.