# What is my waist to height ratio?

Divides your waist circumference by your height and compares the waist-to-height ratio (WHtR) with the 0.5 and 0.6 boundaries for early health risk, with the largest waist that keeps the ratio below 0.5.

- Page: https://www.acalculator.org/health/waist-to-height-ratio-calculator
- JSON spec: https://www.acalculator.org/health/waist-to-height-ratio-calculator.json
- Version: a17aaf5cbb4a

## Default answer

Example with the default inputs (Waist 32 in, Height 5 ft 10 in): A 32 in waist at a height of 5 ft 10 in gives a waist-to-height ratio of 0.457: No increased risk.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| w | Waist | Around your waist, midway between the lowest rib and the top of the hip bone. |
| h | Height | Your height without shoes. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| ratio | Waist-to-height ratio | Waist ÷ height. |
| verdict | Risk group | Below 0.5, 0.5 up to 0.6, or 0.6 and above. |
| limitIn | Waist at a ratio of 0.5 (in) | Half your height, in inches: keep your waist below this. |
| limitCm | Waist at a ratio of 0.5 (cm) | Half your height, in centimetres. |

## Method

Waist-to-height ratio = waist ÷ height; below 0.5 no increased risk, 0.5 to below 0.6 increased risk, 0.6 or more very high risk.

## Assumptions

- The same boundaries apply to adult men and women (Ashwell and Gibson, 2016).
- Waist measured midway between the lowest rib and the top of the hip bone; height without shoes.

## Worked examples

1. w = 0.8636, h = 1.7272 gives ratio = 0.5, verdict = Increased risk, limitIn = 34. Source: Ashwell and Gibson, 2016, Waist-to-height ratio as an indicator of ‘early health risk’, BMJ Open 6:e010159 (WHtR < 0.5 no increased risk, 0.5 to < 0.6 increased risk, ≥ 0.6 very high risk), https://pubmed.ncbi.nlm.nih.gov/26975935/.
2. w = 0.8, h = 1.75 gives ratio = 0.457143, verdict = No increased risk, limitCm = 87.5. Source: Ashwell and Gibson, 2016, Waist-to-height ratio as an indicator of ‘early health risk’, BMJ Open 6:e010159 (WHtR < 0.5 no increased risk, 0.5 to < 0.6 increased risk, ≥ 0.6 very high risk), https://pubmed.ncbi.nlm.nih.gov/26975935/.
3. w = 0.96012, h = 1.6002 gives ratio = 0.6, verdict = Very high risk. Source: Ashwell and Gibson, 2016, Waist-to-height ratio as an indicator of ‘early health risk’, BMJ Open 6:e010159 (WHtR < 0.5 no increased risk, 0.5 to < 0.6 increased risk, ≥ 0.6 very high risk), https://pubmed.ncbi.nlm.nih.gov/26975935/.

## FAQ

### How do I calculate my waist to height ratio?

Divide your waist by your height, both in the same unit. A 34 in waist at 68 in (5 ft 8 in) gives 34 ÷ 68 = 0.5.

### What is a good waist to height ratio?

Below 0.5. Ashwell and Gibson (BMJ Open, 2016) used three groups: below 0.5 for no increased risk, 0.5 up to 0.6 for increased risk, and 0.6 or more for very high risk.

### What does “keep your waist to less than half your height” mean?

It is the 0.5 boundary in plain words. If you are 175 cm tall, keep your waist below 87.5 cm; at 5 ft 8 in, below 34 in. The page shows this limit as “Waist at a ratio of 0.5”.

### Is the waist to height ratio better than BMI?

Ashwell and Gibson found that a single 0.5 boundary for waist-to-height ratio picked out more people at early health risk than a matrix of BMI and waist circumference, including some with a healthy BMI. It is a quick screen, not a diagnosis.

### Does the 0.5 boundary work for men and women?

Yes. The same boundary is used for adult men and women, which is one reason it is simple to use. Height already scales the waist to body size.

### How should I measure my waist?

Stand relaxed, breathe out gently, and measure midway between your lowest rib and the top of your hip bone with the tape level and snug. Measure your height without shoes.

## Sources

- Ashwell, M. and S. Gibson (2016). Waist-to-height ratio as an indicator of ‘early health risk’: simpler and more predictive than using a ‘matrix’ based on BMI and waist circumference. BMJ Open 6:e010159. https://pubmed.ncbi.nlm.nih.gov/26975935/ (retrieved 2026-10-01)
- NIST Special Publication 811, Appendix B: 1 in = 2.54 cm exactly. https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-01)