Waist Measurements: Waist-to-Height and Waist-to-Hip Ratios
Where the body stores fat matters as well as how much there is. Fat carried around the middle is more closely linked to health risk than fat stored on the hips and thighs, and a simple tape measure can pick that up when weight and BMI cannot.
This article covers how to take a reliable waist measurement, what the usual waist limits mean, and how to turn your measurements into two ratios: waist-to-height and waist-to-hip. All of these are screening tools for adults, not diagnoses.
How to measure your waist
Small differences in technique change the number, so follow the same steps each time.
- Stand upright, relaxed, with your feet together and your abdomen unforced. Measure against bare skin or thin clothing.
- Find the midpoint between the lowest rib and the top of the hip bone. This is the position used in World Health Organization guidance. Some protocols measure at the navel instead, which gives a slightly different value, so choose one and stay with it.
- Wrap the tape level around the body so it is parallel to the floor, snug but not squeezing the skin.
- Read the measurement at the end of a normal breath out, without holding your breath or pulling your stomach in.
- Repeat once and use the average if the two readings differ.
For the hips, measure around the widest part of the buttocks, again with the tape level. Use the same units (all centimetres or all inches) for every figure you intend to compare.
Waist circumference on its own
The simplest approach is to compare the waist measurement with commonly used limits for adults. The values below follow World Health Organization guidance, which was developed mainly from data on people of European descent.
| Adults | Increased risk | Substantially increased risk |
|---|---|---|
| Men | 94 cm (about 37 in) or more | 102 cm (about 40 in) or more |
| Women | 80 cm (about 31.5 in) or more | 88 cm (about 35 in) or more |
Lower limits are used for some populations, particularly people of South and East Asian descent, so the limits that apply to you may differ. These figures also do not allow for body size: a very tall person and a very short person are held to the same number.
Waist-to-height ratio
Dividing the waist by height adjusts the measurement for body size. Both numbers must be in the same units, and the units then cancel out, so the ratio is the same whether you use centimetres or inches.
waist-to-height ratio = waist ÷ heightBoth measurements in the same unit.
A widely quoted rule of thumb is to keep your waist to less than half your height, which is a ratio below 0.5. A commonly used scale treats 0.5 to 0.59 as increased risk and 0.6 or more as high risk.
Worked example: a person is 172 cm tall with an 86 cm waist. The ratio is 86 ÷ 172 = 0.50, right on the boundary. Another person is 160 cm tall with an 88 cm waist: 88 ÷ 160 = 0.55, in the increased-risk band. Half of 160 cm is 80 cm, so that waist would need to be 8 cm smaller to reach 0.5.
A quick check is to halve your height and compare it with your waist. If the waist is bigger than half the height, the ratio is above 0.5.
Waist-to-hip ratio
The waist-to-hip ratio compares the waist with the hips. It describes fat distribution rather than body size, and two people with the same waist can have different ratios if their hips differ.
waist-to-hip ratio = waist ÷ hipBoth measurements in the same unit.
World Health Organization guidance describes abdominal obesity as a ratio of 0.90 or more in men and 0.85 or more in women.
Worked example: a waist of 86 cm and hips of 100 cm give 86 ÷ 100 = 0.86. That is below the 0.90 figure for men but just above the 0.85 figure for women, which shows how the sex-specific limits change the reading of the same number.
Waist and hip measurements are also the inputs to the body shape calculator, which takes bust, waist and hip and names a shape such as pear or hourglass. That is a style guide, not a health measure, and it does not use the risk limits above.
Limits and context
- Measurement error is real. A difference of a centimetre or two between sessions is normal. Look at changes over weeks, not days.
- Not for everyone. The cut-offs are for adults. Children have their own growth standards, and pregnancy changes the waist for reasons unrelated to fat.
- One of several signals. Waist measurements are most useful alongside BMI, blood pressure and blood tests. See what BMI can and cannot tell you for how the pieces fit together.
If you also want your BMI, the BMI calculator takes only height and weight. The waist also feeds tape-measure estimates of body fat, covered in how to estimate body fat with a tape measure.
This article is general education, not medical advice. A doctor or other qualified health professional can interpret your measurements in light of your age, background and medical history.
- BMI Calculator: Enter your height and weight to see your body mass index, the weight category it falls into and how far you sit from the edges of the healthy range. The guide explains the formula, the categories and what BMI can and cannot tell you.
- Body Fat Calculator: Enter your age and a few tape measurements to estimate your body fat percentage, fat mass and lean mass. The guide explains the Navy formula, how to measure correctly and how the categories work.
- Body Shape Calculator: Measure your bust, waist and hips, enter them in inches or centimetres, and the calculator names the closest of four common body shapes. The guide shows how to measure and exactly which ratios decide the result.
This article is general information, not professional advice. See our Disclaimer and Editorial Policy.
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