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Waist-to-Height and Waist-to-Hip Ratio Calculator
Two or three tape measurements give you the ratios doctors use to judge fat around the middle — and a body-fat estimate from the same numbers.
Short answer
Under 0.5: keep your waist to less than half your height. NICE guidance for adults treats 0.4–0.49 as healthy, 0.5–0.59 as increased health risk and 0.6 or more as high risk. A 175 cm (5 ft 9 in) adult should keep their waist under about 87.5 cm (34.4 in).
Where you carry fat matters as much as how much you carry. Fat around the abdomen is linked more strongly to heart disease and type 2 diabetes than fat on the hips or thighs, and BMI cannot see the difference.
Waist-to-height ratio is the simplest way to check: one tape measure, one division, one number to stay under.
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Waist-to-Height Ratio Calculator
Waist-to-height ratio, waist-to-hip ratio and a body-fat estimate from three tape measurements.
Widest part of the buttocks.
Healthy: 0.49
A tape measure checks one place. A body scan checks six.
SlimAI's AI Body Assessment sizes six regions, including your waist and hips, from two photos, and uses relative fat mass as one of four estimates behind your body-fat figure. Full results are part of SlimAI Pro.
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Ratios are screening measures for fat stored around the middle, not a diagnosis. Measure your waist midway between your lowest rib and the top of your hip bone, after breathing out, with the tape level. These bands are for adults and do not apply during pregnancy. Not medical advice.
The Waist-to-Height Bands
NICE uses these bands for adults. The boundary that matters most is 0.5.
Healthy
Your waist is less than half your height. Central fat is in the range associated with the lowest risk.
Increased risk
Fat around the middle is above the healthy band. Worth acting on even if your BMI is normal — a third of adults with a "healthy" BMI-and-waist result in one UK analysis were above 0.5.
High risk
Central fat is in the highest band. A steady calorie deficit and more activity usually bring the waist down first, and a health professional should be involved.
Why the middle matters more than the scale
Fat stored inside the abdomen, around the organs, is more metabolically active than fat under the skin elsewhere, and it tracks more closely with blood pressure, blood sugar and cholesterol. A tape measure around the waist is a cheap proxy for it.
In a UK analysis of national survey data, 35% of adults judged "no increased risk" by the usual BMI-and-waist matrix had a waist-to-height ratio of 0.5 or more. And among adults with a healthy BMI, those at 0.5 or above had significantly higher levels of several cardiometabolic risk factors than those below it.
One tape measurement is a snapshot
SlimAI’s AI Body Assessment sizes six body regions, including your waist and hips, from two photos, and charts your body-fat trend scan after scan. Full results are part of SlimAI Pro.
3-day free trial · Cancel anytime · No card charged during trial
Waist-to-height or waist-to-hip?
Waist-to-height is the simpler of the two. One boundary works for men and women and across heights, and a waist that is too big for your height is a waist that is too big.
Waist-to-hip compares your waist with your hips, so it rewards a wide frame and can look fine on someone with a large waist and large hips. Its WHO cut-offs differ by sex: 0.90 for men and 0.85 for women. Use it alongside waist-to-height rather than instead of it.
How to measure your waist properly
Find the bottom of your lowest rib and the top of your hip bone. Wrap the tape around the midpoint between the two, level all the way round, snug but not pressing into the skin.
Breathe out normally and measure at the end of the breath. Measure your hips at the widest part of your buttocks. Same time of day, same conditions, every time — before breakfast is easiest.
Waist Limits by Height
The waist measurement at each waist-to-height boundary. Stay under the middle column for the healthy band.
| Height | Lower edge (0.4) | Increased risk from (0.5) | High risk from (0.6) |
|---|---|---|---|
| 152 cm (5 ft 0 in) | 61 cm (24.0 in) | 76 cm (30.0 in) | 91 cm (36.0 in) |
| 160 cm (5 ft 3 in) | 64 cm (25.2 in) | 80 cm (31.5 in) | 96 cm (37.8 in) |
| 168 cm (5 ft 6 in) | 67 cm (26.4 in) | 84 cm (33.0 in) | 101 cm (39.6 in) |
| 175 cm (5 ft 9 in) | 70 cm (27.6 in) | 88 cm (34.5 in) | 105 cm (41.4 in) |
| 183 cm (6 ft 0 in) | 73 cm (28.8 in) | 91 cm (36.0 in) | 110 cm (43.2 in) |
| 191 cm (6 ft 3 in) | 76 cm (30.0 in) | 95 cm (37.5 in) | 114 cm (45.0 in) |
Rounded to the nearest centimetre and tenth of an inch. Waist-to-hip cut-offs: 0.90 for men, 0.85 for women (WHO).
How to Calculate Waist-to-Height Ratio
All you need is a tape measure and your height.
- 1
Measure your waist
Midway between your lowest rib and the top of your hip bone, after breathing out, tape level.
- 2
Use the same unit for height
Centimetres with centimetres, inches with inches. The ratio has no unit.
- 3
Divide waist by height
86 cm ÷ 175 cm = 0.49, just inside the healthy band.
- 4
For waist-to-hip, divide waist by hips
86 cm ÷ 98 cm = 0.88: under 0.90 for a man, above 0.85 for a woman.
The Formulas Behind This Calculator
Computed in your browser. Nothing is uploaded and nothing is stored between visits.
Waist-to-height ratio
WHtR = waist ÷ heightBands: under 0.4 low, 0.4–0.49 healthy, 0.5–0.59 increased risk, 0.6+ high risk.
Waist-to-hip ratio
WHR = waist ÷ hipsSubstantially increased risk at 0.90+ for men and 0.85+ for women.
Relative fat mass
RFM = 64 − 20 × (height ÷ waist) · women: 76 − 20 × (height ÷ waist)A body-fat percentage estimate from the same two measurements.
Waist circumference alone
men: 94 cm increased, 102 cm high · women: 80 cm increased, 88 cm highWHO cut-offs, shown as an extra check when your waist crosses one.
Sources and method
- NICE — guidance on overweight and obesity for the NHS in England (waist-to-height ratio, 2022 update) — Recommends adults keep their waist to less than half their height, with 0.4–0.49 as healthy central adiposity, 0.5–0.59 increased and 0.6 or more high.
- Ashwell M, Gibson S (2016) — BMJ Open — UK national survey data: 35% of adults classed as "no increased risk" by a BMI-and-waist matrix had a waist-to-height ratio of 0.5 or more. Among adults with a healthy BMI, a ratio of 0.5 or more went with significantly higher levels of some cardiometabolic risk factors.
- World Health Organization (2008) — Waist circumference and waist–hip ratio, expert consultation — Waist-to-hip ratio of 0.90 or more in men and 0.85 or more in women, and waist circumference above 102 cm (men) or 88 cm (women), mark substantially increased metabolic risk.
- Woolcott OO, Bergman RN (2018) — Scientific Reports — Relative fat mass: a body-fat percentage estimate from height and waist, validated against DXA.
FAQ
Still Wondering About SlimAI
What is a healthy waist-to-height ratio?
What is a healthy waist-to-height ratio?Between 0.4 and 0.49 for adults. In plain terms: keep your waist to less than half your height. At 0.5–0.59 health risk is increased, and at 0.6 or more it is high.
What waist-to-height ratio does the NHS use?
What waist-to-height ratio does the NHS use?The 0.5 boundary from NICE, which writes guidance for the NHS in England: keep your waist to less than half your height. NICE treats 0.4–0.49 as healthy, 0.5–0.59 as increased health risk and 0.6 or more as high. This calculator uses the same bands.
How do I calculate my waist-to-height ratio?
How do I calculate my waist-to-height ratio?Divide your waist measurement by your height, both in the same unit. An 86 cm waist at 175 cm tall is 0.49. In inches, a 34-inch waist at 69 inches tall is also 0.49.
What is a healthy waist-to-hip ratio?
What is a healthy waist-to-hip ratio?Below 0.90 for men and below 0.85 for women, according to the WHO. At or above those figures, metabolic risk is substantially increased.
Is waist-to-height ratio better than BMI?
Is waist-to-height ratio better than BMI?It catches something BMI misses. BMI cannot tell where fat is stored, while waist-to-height measures fat around the middle directly. In one UK analysis, a third of adults with a reassuring BMI-and-waist result were above 0.5. Using both is better than either alone.
Where should I measure my waist?
Where should I measure my waist?Midway between your lowest rib and the top of your hip bone, which is usually a little above the belly button. Keep the tape level, breathe out normally, and measure at the end of the breath.
Do these bands apply to everyone?
Do these bands apply to everyone?They are for adults. They do not apply during pregnancy, and some ethnic groups carry higher risk at lower waist sizes, so a health professional may use tighter thresholds for you.
Does SlimAI measure my waist?
Does SlimAI measure my waist?SlimAI’s AI Body Assessment sizes six regions, including your waist and hips, from two photos, and uses relative fat mass as one of four estimates behind your body-fat figure. Full results are part of SlimAI Pro.
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