Waist-to-Height Ratio Calculator
Divide your waist by your height to see if you keep your waist to less than half your height, and how much room you have.
Measure halfway between your lowest rib and the top of your hip bone, standing up, after a normal breath out. Keep the tape level and snug, not tight.
Hips around the widest part of your bottom. Leave the hip box blank to skip the waist-to-hip ratio. The target ratio is 0.5 unless you change it.
Want the full picture? Try the BMI calculator or the body fat calculator.
How your waist-to-height ratio is worked out
Your numbers, step by step. Ratio = waist ÷ height, both in the same unit.
- 1
Measure your waist
Waist: 84 cm
- 2
Measure your height
Height: 175 cm
- 3
Divide waist by height
84 ÷ 175 = 0.48
- 4
Find your band
0.48 → healthy
Read more: the formula, a worked example, how to measure and the NICE and WHO cut-offs
What the ratio tells you
Your waist-to-height ratio compares the size of your waist with your height. It's a simple way to see how much fat you carry around your middle, which is linked to a higher risk of problems such as type 2 diabetes and heart disease. The UK's NICE guideline puts it simply: keep your waist to less than half your height. The same line is used for men and women and for people of all ethnic backgrounds.
The formula
Waist-to-height ratio = waist ÷ height, with both in the same unit (cm and cm, or inches and inches)
The units cancel out, so the ratio is the same in centimetres or inches. The largest waist that keeps you under 0.5 is anything under half your height, and the healthy band starts at 0.4 × your height. We judge the band on the exact ratio. If rounding to two decimals would push the figure across a line (for example 0.4994 to 0.50), we show three decimals instead (0.499), so the number and the band always agree.
Worked example
Someone 175 cm tall with an 84 cm waist. 84 ÷ 175 = 0.48, which is in the 0.4 to 0.49 healthy band. Half their height is 175 ÷ 2 = 87.5 cm, so their waist is 87.5 − 84 = 3.5 cm under the line. The waist range for the healthy band is 0.4 × 175 = 70 cm up to under 87.5 cm.
In inches: 5 ft 9 in is 69 in. With a 33 in waist, 33 ÷ 69 = 0.478…, shown as 0.48, the same band.
Advanced, with 98 cm hips: the waist-to-hip ratio is 84 ÷ 98 = 0.857…, shown as 0.86. For a man that's under the WHO line of 0.90. For a woman it would be at or above the 0.85 line, which the WHO links to a substantially increased risk.
NICE waist-to-height bands (adults)
| Waist ÷ height | What it means |
|---|---|
| Below 0.4 | Below NICE's healthy band. NICE gives no category for this; if you're unsure, talk to a doctor. |
| 0.4 to 0.49 | Healthy |
| 0.5 to 0.59 | Increased health risk |
| 0.6 or more | High health risk |
NICE (UK) classifies central adiposity this way for adults with a BMI under 35, of both sexes and all ethnicities, including adults with high muscle mass, and suggests using it alongside BMI. For children and young people aged 5 and over, NICE points to the NHS calculator. It is not meant for pregnancy.
Source: NICE guideline NG246, recommendations 1.9.14 and 1.9.15, checked 13 October 2026. The 0.4 to 0.49, 0.5 to 0.59 and 0.6 or more bands are NICE's; the band below 0.4 is not a NICE category.
Waist-to-hip ratio and waist size (WHO)
| Measure | Men | Women |
|---|---|---|
| Waist-to-hip ratio, substantially increased risk | 0.90 or more | 0.85 or more |
| Waist size, increased risk | over 94 cm (37 in) | over 80 cm (31.5 in) |
| Waist size, substantially increased risk | over 102 cm (40 in) | over 88 cm (34.6 in) |
From the World Health Organization expert consultation on waist circumference and waist–hip ratio (2008). The waist size cut-offs come from people of European background; lower cut-offs are often used for people of South Asian, Chinese and some other backgrounds. We judge the waist-to-hip ratio on the figure shown, rounded to two decimals.
How to measure
- Waist: find the bottom of your lowest rib and the top of your hip bone. Measure halfway between them, standing up, after a normal breath out. Keep the tape level and snug, not tight. This is how NICE and the WHO describe it; it's often a little above your belly button.
- Height: without shoes, standing straight against a wall.
- Hips: around the widest part of your bottom, with the tape level.
- No tape? Try the string test: cut a piece of string as long as you are tall, fold it in half and wrap it around your waist. If it meets, your waist is less than half your height.
Its limits
- It's a quick check, not a diagnosis. It doesn't measure body fat directly.
- Where the tape sits changes the result, so measure the same way each time and watch the trend.
- It's not meant for pregnancy or for young children.
General information, not medical advice. Talk to a doctor about what your numbers mean for you.
Common questions
What is a healthy waist-to-height ratio?
For adults, NICE (UK) puts 0.4 to 0.49 in the healthy band. 0.5 to 0.59 means increased health risk and 0.6 or more means high health risk. The simple rule is to keep your waist to less than half your height.
How do I work out my waist-to-height ratio?
Divide your waist size by your height, both in the same unit. For example, an 84 cm waist and a height of 175 cm give 84 ÷ 175 = 0.48. In inches, a 33 in waist and a height of 69 in give 0.48 too.
Where should I measure my waist?
Find the bottom of your lowest rib and the top of your hip bone, and measure halfway between them. Stand up straight, breathe out normally, and keep the tape level and snug, not tight.
Is waist-to-height ratio better than BMI?
It's a useful extra. BMI looks only at weight and height, while waist-to-height ratio shows fat around the middle, which is linked to health risk. NICE suggests using it alongside BMI for adults with a BMI under 35.
Is the 0.5 line the same for men and women?
Yes. The NICE advice to keep your waist to less than half your height is the same for men and women and for people of all ethnic backgrounds. The waist-to-hip ratio cut-offs from the WHO are different: 0.90 for men and 0.85 for women.
Who should not use this ratio?
NICE uses these bands for adults with a BMI under 35, of both sexes and all ethnicities, including adults with high muscle mass. For children and young people aged 5 and over, NICE points to the NHS waist-to-height ratio calculator. It is not meant for pregnancy. Talk to a doctor about what your numbers mean for you.
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