Waist-to-Height Ratio and Healthy Waist Size: The Cutoffs

Your BMI is "normal," but your doctor still measured your waist? That's no accident. The link between waist size and health is one of the best established in nutrition: fat stored around your abdomen is more strongly associated with type 2 diabetes and heart disease than fat stored elsewhere. In this guide, you'll find the waist to height ratio (simpler than it sounds), the WHO healthy waist size cutoffs, the right way to measure yourself and what you can do if your number is high.

In short

• WHO cutoffs (people of European descent): increased risk above 80 cm (31.5 in) for women and 94 cm (37 in) for men; substantially increased risk above 88 cm (35 in) and 102 cm (40 in).
• Waist-to-height ratio: stay under 0.5, in other words, keep your waist less than half your height.
• Why it matters: waist size reflects belly fat, which BMI can't see.
• How to measure: halfway between your lowest rib and the top of your hip bone, standing, at the end of a breath out.
• Good news: your waist responds well to physical activity, even when your weight barely moves.

Why is waist size a health indicator?

Not all fat is equal. Subcutaneous fat, on your hips and thighs, is relatively weakly linked to metabolic disease. Visceral fat, packed around the organs in your abdomen (liver, intestines), is much more active: it releases substances that promote inflammation and insulin resistance.

Measuring visceral fat directly requires a CT scan, an MRI or a DEXA scan. Waist size is a simple, free and fairly reliable estimate of it. In many studies, a large waist is associated with a higher risk of:

• type 2 diabetes;
• high blood pressure;
• cardiovascular disease;
• fatty liver disease;
• metabolic syndrome.

That's why waist size is one of the measurements recommended alongside BMI, as our guide on how to calculate BMI and its limits explains.

What is a healthy waist size? The WHO cutoffs

The World Health Organization has defined two risk levels for adults of European descent.

The 88 cm (35 in) cutoff for women and 102 cm (40 in) for men is also the one most often used to define abdominal obesity in clinical practice.

Are these cutoffs the same for everyone?

No. A few nuances apply:

• Ethnic background: the International Diabetes Federation (IDF) suggests lower cutoffs for people of South Asian, Chinese or Japanese descent, notably 90 cm (35.4 in) for men and 80 cm (31.5 in) for women.
• Height: a 90 cm waist doesn't mean the same thing for someone who is 1.55 m (5 ft 1 in) as for someone who is 1.90 m (6 ft 3 in). That's the main weakness of fixed cutoffs.
• Pregnancy: waist size can't be interpreted during pregnancy or in the months after giving birth.
• Children and teens: there are specific reference charts; your pediatrician or family doctor's advice is essential.

What is the waist-to-height ratio? The "less than half" rule

To fix the weakness of fixed cutoffs, many researchers, including the British nutritionist Margaret Ashwell, have promoted a simple indicator: the waist-to-height ratio.

How do you calculate it?

Divide your waist size by your height, in the same unit:

Ratio = waist (cm) ÷ height (cm)

It works exactly the same in inches: a 32 in waist at 5 ft 7 in (67 in) gives 32 ÷ 67 = 0.48.

Examples:

What are the waist-to-height ratio cutoffs?

In 2022, the UK's National Institute for Health and Care Excellence (NICE) added this ratio to its guidelines for adults with a BMI under 35:

The takeaway is wonderfully simple: keep your waist less than half your height. According to NICE, this rule applies to both sexes and all ethnic backgrounds, including very muscular people.

What about the waist-to-hip ratio?

You'll also come across the waist-to-hip ratio. The WHO considers that it signals abdominal obesity above 0.90 in men and 0.85 in women. It's a little harder to measure, because hip size is prone to errors, and the waist-to-height ratio now tends to be preferred for its simplicity.

Why is waist size sometimes more telling than BMI?

BMI and waist size complement each other. But in some situations, your waist tells a more accurate story.

• In muscular people: a BMI of 27 can mean lots of muscle and little fat. A small waist confirms it.
• In people with a "normal" BMI: a large waist can reveal significant belly fat that BMI doesn't show.
• During a body transformation: when you lose fat and gain muscle, your weight and BMI can stall while your waist shrinks. That's the textbook case of body recomposition.

Waist size also pairs well with body fat percentage and its reference ranges, which tells you how much fat you carry without saying where it sits.

How do you measure your waist correctly?

A reliable measurement takes a few precautions:

1. Stand with your feet hip-width apart, in your underwear.
2. Find the bottom of your lowest rib and the top of your hip bone (iliac crest), on your side.
3. Place the tape measure halfway between the two, level all the way around your body.
4. Snug it without squeezing, breathe normally and read the value at the end of a breath out.
5. Measure twice and keep the average.

For the other areas (hips, chest, arms, thighs), follow our detailed guide on how to take body measurements without mistakes.

To follow how your shape changes, nothing beats a series of photos taken under the same conditions. With Marava, the ghost overlay places last month's photo over the camera screen so you keep the same pose and framing, and the timeline lets you drag a slider across the months to watch your waist change in place.

What should you do if your waist size is high?

First, don't panic: it's a risk indicator, not a diagnosis. And it's one of the indicators that responds best to changes in your habits.

• Move more: regular physical activity, both cardio and strength training, is associated with less visceral fat, sometimes even without much weight loss. The WHO recommends at least 150 to 300 minutes of moderate-intensity activity per week for adults, with muscle-strengthening activities at least two days a week.
• Improve your diet: more fiber, vegetables and legumes; fewer ultra-processed foods, sugary drinks and less alcohol.
• Get enough sleep and manage stress, two factors linked to belly fat gain.
• Track your progress once a month, without measuring yourself every day.

For what the research says in detail (crunches, cardio, fiber, sleep), read our guide on how to lose belly fat without falling for the myths.

Talk to your doctor if your waist is above the substantially increased risk cutoffs, especially if you have a family history of diabetes or heart disease, high blood pressure or unusual fatigue. A blood test (blood sugar, cholesterol) can be helpful.

Conclusion: one tape measure, one simple rule

The link between waist size and health is solid: above 80 cm (31.5 in) for women and 94 cm (37 in) for men (WHO cutoffs for people of European descent), risk goes up. The waist to height ratio refines that benchmark with an easy rule: keep your waist under half your height.

Measured once a month, your waist also becomes an excellent indicator of progress. To find out how long it takes to see these changes, read our article on how long it really takes to see results.