BMI cutoffs are population-level risk boundaries set by the WHO and CDC. They flag risk — they do not diagnose.
Under 18.5 = underweight. 18.5–24.9 = healthy. 25–29.9 = overweight. 30+ = obesity (Class I 30–34.9, II 35–39.9, III 40+).
Muscular athletes get flagged as overweight. Older adults with low muscle can sit in the healthy band while carrying high body fat.
Pair BMI with waist-to-height ratio for a better single-glance picture.
Check the full BMI chart with categories.
Open the BMI chart →
BMI can label muscular athletes as overweight or obese. Here's when BMI misses the mark and what to use instead.
The clearest waist guideline for women, based on the NHS and Ashwell Waist-to-Height ratio — no charts, just one rule.
How age changes your healthy weight range, and the simple WHO/CDC formula that answers "how much should I weigh?".