Medical

BMI Calculator Guide — WHO Categories & Clinical Use

Calculate body mass index from height and weight. WHO categories, limitations for athletes, and when to use BMI in screening.

Published June 1, 2025 · 1 min read

Written by Ethan Brooks · Editor-in-Chief & Product Lead

Reviewed by James Cole

Last reviewed January 15, 2026 · Editorial policy

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What BMI measures

Body Mass Index (BMI) relates weight to height and is widely used for population-level obesity screening. It does not distinguish muscle from fat — athletes may read "overweight" despite low body fat.

How to use the calculator

Open the BMI calculator.
Enter height (cm or ft/in) and weight (kg or lb).
Read your BMI and WHO category (underweight, normal, overweight, obese).

When BMI is useful

Primary care intake and wellness screenings
Patient education handouts
Tracking trend over time (same scale, same time of day)

More clinical scores: medical calculators hub · Long-tail: BMI for women

Disclaimer: These calculators are educational aids only. They do not diagnose, treat, or replace licensed medical advice. Always follow local clinical protocols.

Sources & references

Primary references used when researching and fact-checking this guide. See our editorial methodology.

Adobe PDF Reference — encryption — Adobe
PDF password protection and encryption standards (ISO 32000).
Ghostscript documentation — PDF settings — Artifex Software
Compression level behavior and PDF output settings.