Waist-to-height ratio calculator

Measure your waist, and the calculator shows your waist-to-height ratio and how your waist size compares with the cut-offs used in guidelines.

How to measure your waist

It is easy to get different numbers depending on where the tape sits. This is the method the WHO recommends:

1. Stand upright with your arms by your sides and your weight on both feet.
2. Find your lowest rib and the top of your hip bone at the side of your body. Place the tape midway between them.
3. Keep the tape level all the way round, snug but without pressing.
4. Breathe normally a few times and read the tape after a normal breath out.

Some guides measure at the belly button instead. That can give slightly different numbers, so the most important thing is to measure in the same place each time if you want to follow changes.

Waist-to-height ratio: under 0.5

NICE, which sets health guidance in the UK, uses a simple rule: keep your waist to less than half your height. The ratio is your waist divided by your height, and it works for all sexes and ethnic backgrounds. NICE recommends using it alongside BMI for adults with a BMI under 35.

Waist-to-height ratio	What NICE says
0.40–0.49	No increased health risk
0.50–0.59	Increased health risk
0.60 and above	Further increased health risk

Waist size cut-offs for women and men

Many guidelines use two cut-offs for waist size. The first is 80 cm for women and 94 cm for men, and the second is 88 cm and 102 cm. The WHO's expert report notes that these numbers were set as examples and that the right cut-off can differ between populations.

A larger waist mainly reflects fat inside the abdomen, around the organs. That type of fat is more closely linked to type 2 diabetes and heart disease than fat on the hips and thighs. Sleep, food and movement all affect it, and our weight loss page has the habits with the best evidence.

Frequently asked questions

What is a healthy waist-to-height ratio?

NICE, which sets health guidance in the UK, recommends keeping your waist to less than half your height, a ratio under 0.5. From 0.5 to 0.59 it counts as increased health risk, and from 0.6 as further increased risk, in the population as a whole.

What is a normal waist size for women and men?

Two sets of cut-offs are common. For women, the first is 80 cm and the second 88 cm; for men, 94 cm and 102 cm. They describe risk in large groups and say less about one person than about the population.

How do I measure my waist correctly?

Stand upright and place the tape midway between your lowest rib and the top of your hip bone. Keep it level and snug without pressing, and read it after a normal breath out.

Is waist-to-height ratio better than BMI?

It says more about fat around the waist, which is linked to the risk of type 2 diabetes and heart disease. NICE recommends using it alongside BMI for adults with a BMI under 35.

Sources

• NICE (2025): Overweight and obesity management (NG246)
• NICE: Keep the size of your waist to less than half of your height
• WHO (2011): Waist circumference and waist–hip ratio. Report of a WHO expert consultation

The calculator uses cut-offs that describe risk in large groups. It does not replace an assessment by a doctor, and the limits do not apply during pregnancy. The numbers you enter stay in your browser and are not stored.