Where does your number sit?

The threshold bands

Ratio	Band	What it indicates
0.00 to 0.39	Below the healthy range	NICE notes that a ratio below 0.4 may indicate being underweight and is worth raising with a clinician.
0.40 to 0.49	Healthy range	Waist is less than half your height. This is the band NICE identifies as healthy for all adults.
0.50 to 0.59	Increased health risk	NICE classifies 0.5 to 0.59 as increased central adiposity and increased health risk.
0.60 and above	Further increased health risk	NICE classifies 0.6 and above as further increased health risk and suggests discussing it with a clinician.

Why this number matters

Where fat sits matters more than how much you weigh. Fat around the abdomen sits against the liver and pancreas and behaves differently from fat on the hips and thighs, which is why two people at the same BMI can have very different metabolic profiles.

Waist-to-height ratio captures that in a way BMI cannot, and it does it without needing separate cutoffs for men and women or for different heights. It also performs more consistently across ethnic groups than BMI, which systematically misclassifies risk for people of South Asian descent in particular.

The rule of thumb behind the threshold is simple enough to remember: keep your waist to less than half your height.

How to measure it properly

Measure your waist at the midpoint between the bottom of your ribs and the top of your hip bones ... roughly level with your navel for most people. Stand up, breathe out normally, and do not pull the tape tight enough to compress the skin. Measure directly against skin or over a thin layer.

Divide your waist by your height in the same units. A 34-inch waist and a 70-inch height gives 34 divided by 70, which is 0.49. Centimetres work identically: 86 cm divided by 178 cm is also 0.48.

The calculator below takes waist and height in either inches or centimetres and does the division for you.

How to read your result

Unlike every other benchmark on this site, this one does not shift with age. NICE applies the same bands to all adults, so a ratio of 0.52 means the same thing at 45 as it does at 75.

These thresholds are screening bands, not diagnoses. They are designed to indicate who should look further, and they say nothing on their own about blood pressure, blood glucose, or lipids.

The guidance does not apply to people with a BMI over 35, where waist measurement becomes unreliable, or to pregnant people.

Where this data comes from

Source: NICE obesity assessment guidance
Citation: National Institute for Health and Care Excellence. Obesity: identification, assessment and management (CG189), updated recommendation on waist-to-height ratio, 2023.
Reference population: General adult population. Not validated for adults with BMI over 35, or during pregnancy.
Measurement note: Waist measured at the midpoint between the lowest rib and the iliac crest, at the end of a normal exhale.
Last reviewed: 2026-09-09