On this page
The measures at a glance
| Measure | Needs | Best for |
|---|---|---|
| BMI | Height, weight | Quick screening, comparing groups1 |
| BMI Prime | Height, weight | Seeing how far from BMI 25 you are |
| Waist-to-height ratio | Height, waist | Fat around the stomach, any height |
| Relative fat mass | Height, waist | Estimating body fat without a scale2 |
| Body fat percentage | Several methods | Separating fat from muscle |
| New BMI | Height, weight | Very short or very tall people |
| Ponderal Index | Height, weight | Infants and very tall or short people |
| A Body Shape Index | Height, weight, waist | Research on waist-related risk3 |
Which should you use?
| What BMI shows | What it doesn't show |
|---|---|
| Your weight compared with your height | Where fat is stored, such as around the stomach |
| A quick screening number from a scale and a height | How much of your weight is fat and how much is muscle |
| A way to compare groups of people | What a child's BMI means, without percentiles for age and sex |
- For a quick check: BMI plus waist-to-height ratio covers most people well.
- If you're muscular: add a body-fat estimate. BMI for athletes.
- For children: none of these replace BMI-for-age percentiles. BMI for kids.
Frequently asked questions
What's better than BMI?
No single measure is best for everyone. Waist-to-height ratio is often a better guide to health risk, because it shows fat around the stomach. Using it alongside BMI gives a fuller picture.
Do I need special equipment?
No. A tape measure for your waist is enough for most of these measures.
Sources
Kept up to dateLast updated October 9, 2026
Private by designYour numbers never leave your device
This page is for education and is not medical advice. Talk with a healthcare professional about your weight and health.
