Here's a little test you can do right now with a piece of string. Cut it to match your height. Fold it in half. Then wrap it around your waist. Does it meet or overlap? If so, your waist is less than half your height. That simple string trick is really checking your waist to height ratio, and it's one of the easiest health checks you can do at home.
Let me explain what the number means, how to measure it well, and what to do with it.
What is waist to height ratio?
Waist to height ratio (often shortened to WHtR) is your waist size divided by your height:
Waist to height ratio = waist ÷ height
Use the same units for both. Inches and inches work. Centimeters and centimeters work too. The answer is the same either way.
For example, a woman who is 5 ft 5 in (65 in, or 165 cm) tall with a 32 in (81 cm) waist has a ratio of 32 ÷ 65 = 0.49.
Why your waist matters
Your weight tells you how much of you there is. Your waist tells you something about where it sits.
The National Heart, Lung, and Blood Institute (NHLBI) explains that carrying most of your fat around your waist, rather than your hips, raises your risk of heart disease and type 2 diabetes. BMI can't see that. The CDC calls BMI a screening measure that should be looked at along with other factors. Your waist is one of the easiest "other factors" to check yourself.
The healthy waist to height ratio range (NICE)
In 2025, NICE, the health guidance body in England, updated its guideline on overweight and obesity (NG246). Its advice is short and easy to remember: keep your waist to less than half your height.
| Waist to height ratio | What NICE says |
|---|---|
| Under 0.5 | Your waist is less than half your height. This is the NICE goal. |
| 0.5 to 0.59 | Increased central fat, with increased health risks |
| 0.6 or more | High central fat, with further increased health risks |
What I find really useful here is who it works for. NICE says the ratio can be used for adults with a BMI under 35, for both men and women, for all ethnic groups, and for people with a lot of muscle. That last part is a big deal for gym-goers, whose BMI can look high because of muscle.
NICE's advice on this ratio covers adults with a BMI under 35. If yours is 35 or higher, your doctor is the best person to guide you.
Waist to height ratio chart (inches and cm)
Every number in this chart is just your height multiplied by 0.5 and 0.6.
| Height | Waist for a ratio of 0.5 | Waist for a ratio of 0.6 |
|---|---|---|
| 5 ft 0 in (152 cm) | 30 in (76 cm) | 36 in (91 cm) |
| 5 ft 2 in (157 cm) | 31 in (79 cm) | 37.2 in (94 cm) |
| 5 ft 4 in (163 cm) | 32 in (81 cm) | 38.4 in (98 cm) |
| 5 ft 6 in (168 cm) | 33 in (84 cm) | 39.6 in (101 cm) |
| 5 ft 8 in (173 cm) | 34 in (86 cm) | 40.8 in (104 cm) |
| 5 ft 10 in (178 cm) | 35 in (89 cm) | 42 in (107 cm) |
| 6 ft 0 in (183 cm) | 36 in (91 cm) | 43.2 in (110 cm) |
| 6 ft 2 in (188 cm) | 37 in (94 cm) | 44.4 in (113 cm) |
| 6 ft 4 in (193 cm) | 38 in (97 cm) | 45.6 in (116 cm) |
How to read it: find your height. If your waist is under the first number, your ratio is under 0.5. If it falls between the two numbers, you're in the 0.5 to 0.59 zone. At or above the second number, you're at 0.6 or more.
How to measure your waist the right way
This part is simpler than it sounds. The NHLBI gives these steps:
- Stand up straight.
- Place a tape measure around your middle, just above your hipbones.
- Breathe out normally, then measure.
A WHO expert report on waist measurement adds two helpful details. Keep the tape parallel to the floor, and make it snug but not so tight that it squeezes. I'd also measure at the same time of day each time, so your numbers are easy to compare.
Then pop your numbers into our waist-to-height ratio calculator. It does the division for you.
A worked example
I ran two example people through the math:
- A woman, 5 ft 5 in (165 cm) with a 32 in (81 cm) waist: 0.49. That's under 0.5.
- A man, 5 ft 10 in (178 cm) with a 38 in (97 cm) waist: 0.54. That's in the 0.5 to 0.59 range, which NICE links to increased health risks.
Waist to height ratio vs waist-to-hip ratio
You may have heard of waist-to-hip ratio too. It's a different check, and it's worth knowing both.
Waist-to-hip ratio = waist ÷ hips
Measure your hips around the widest part of your bottom (the WHO report calls it the widest portion of the buttocks).
A World Health Organization expert report (from a 2008 meeting, published in 2011) lists these commonly used cut-off points and the risk of metabolic problems that goes with them:
| Measure | Men | Women |
|---|---|---|
| Waist-to-hip ratio | 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) |
The NHLBI uses a similar waist-only line: more than 40 in (102 cm) for men and more than 35 in (88 cm) for women.
Take the man from our example. With a 38 in (97 cm) waist and 40 in (102 cm) hips, his waist-to-hip ratio is 0.95. That's above the WHO line of 0.90 for men.
One more note for readers in India and other parts of Asia. The same WHO report points to studies suggesting lower waist and waist-to-hip cut-offs for Asian populations. That's one more reason the single 0.5 waist to height rule is handy. NICE says it works across all ethnic groups.
So which should you use? Here's my honest view. Waist to height ratio is easier, because you only need one tape measurement and you already know your height. Its single 0.5 line works for men and women of all ethnic groups (in adults with a BMI under 35), while waist-to-hip ratio needs a different line for men and women. But checking both gives you a fuller picture. Try our waist-to-hip ratio calculator next.
What this means for you
If your ratio is under 0.5, that's great news. Keep doing what you're doing and check again every few months.
If it's 0.5 or higher, don't panic. This number can move. The CDC notes that a 5% weight loss, which is 10 lb (4.5 kg) for someone who weighs 200 lb (91 kg), could lower the risk of some chronic diseases like heart disease, prediabetes, and type 2 diabetes. The CDC also says people who lose about 1 to 2 lb (0.5 to 0.9 kg) a week are more likely to keep it off.
A few food steps that can help:
- Build meals around protein, vegetables, and fiber. Our protein calculator gives you a daily target.
- Set a gentle calorie target with our calorie deficit calculator.
- Keep some strength exercise in your week.
If you have diabetes, heart disease, or another health condition, or you take medicines that affect your weight, talk to your doctor or a registered dietitian before making big changes.
For adults over 50
NICE's advice applies to adults, so the same 0.5 line is your guide as you get older. Muscle deserves extra attention now too. The PROT-AGE Study Group suggests 1.0 to 1.2 g of protein per kg of body weight a day for adults over 65. Our guide to protein after 50 shows how to get enough. If you have kidney disease, check with your doctor first.
My take on waist to height ratio
Based on what I've seen, this is one of the most practical health numbers out there. It needs one tape measure, takes two minutes, and has a single rule anyone can remember. It also catches things BMI misses, in both directions. A lifter with a high BMI may find a healthy ratio. Someone with a "normal" BMI may find their waist is creeping up.
I'd check it every month or two, not every day. Waist size changes slowly, and a steady trend tells you more than any one reading.
The bottom line
Your waist to height ratio is your waist divided by your height. NICE's simple goal is to keep your waist to less than half your height, a ratio under 0.5. Measure just above your hipbones after you breathe out, pair it with waist-to-hip ratio for extra detail, and track the trend over time. Ready to find yours? Try our waist-to-height ratio calculator.