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- Waist-to-height ratio = waist ÷ height, both in the same units.
- NICE (UK) categories: 0.4 to 0.49 healthy, 0.5 to 0.59 increased health risk, 0.6 or more further increased risk.
- The simple rule is to keep your waist to less than half your height.
- It works for adults with a BMI under 35 and for children aged 5 and over. This is general information, not medical advice.
How to use the waist-to-height ratio calculator
Choose units
Inches or centimeters. Waist and height must use the same unit.
Measure your waist
Find the bottom of your ribs and the top of your hips, wrap the tape midway between them, breathe out naturally and read the tape.
Enter your height
Without shoes.
Read your result
You get the ratio, the NICE category, the waist that equals half your height and the healthy waist range for your height.
How to calculate waist-to-height ratio
Waist-to-height ratio
Ratio = waist circumference ÷ height
Use the same units for both. A 34 in waist and a 69 in (5 ft 9 in) height give 34 ÷ 69 = 0.49.
Waist-to-height ratio chart
NICE categories
For adults with a BMI under 35, and children and young people aged 5 and over.
- 0.4 to 0.49 Healthy central adiposity, no increased health risks
- 0.5 to 0.59 Increased central adiposity, increased health risks
- 0.6 or more High central adiposity, further increased health risks
The categories apply to both sexes and all ethnicities.
Waist at half your height
The waist size that gives a ratio of 0.5 for each height.
- 5 ft 0 in (152 cm) 30 in (76 cm)
- 5 ft 2 in (157 cm) 31 in (79 cm)
- 5 ft 4 in (163 cm) 32 in (81 cm)
- 5 ft 6 in (168 cm) 33 in (84 cm)
- 5 ft 8 in (173 cm) 34 in (86 cm)
- 5 ft 10 in (178 cm) 35 in (89 cm)
- 6 ft 0 in (183 cm) 36 in (91 cm)
- 6 ft 2 in (188 cm) 37 in (94 cm)
- 6 ft 4 in (193 cm) 38 in (97 cm)
A waist below these figures keeps your ratio under 0.5.
Worked examples
Example 1: healthy range
A 5 ft 9 in (69 in) adult with a 34 in waist.
- Ratio 34 ÷ 69 = 0.49
- Category Healthy central adiposity
- Waist at half height 34.5 in
Just under the 0.5 line.
Example 2: increased risk
The same person with a 38 in waist.
- Ratio 38 ÷ 69 = 0.55
- Category Increased central adiposity
- Above half height by 3.5 in
Bringing the waist under 34.5 in would move the ratio below 0.5.
Example 3: metric
A 175 cm adult with an 86 cm waist.
- Ratio 86 ÷ 175 = 0.49
- Category Healthy central adiposity
The ratio is the same in any unit.
Why waist-to-height ratio matters
Fat stored around the middle (central adiposity) is linked to higher risks of type 2 diabetes, heart disease and other conditions, even in people whose BMI looks healthy. Waist-to-height ratio captures this in a single number that scales with height, so the same 0.5 cut-off works for short and tall people. In 2022 NICE recommended that adults with a BMI under 35 measure and use their waist-to-height ratio alongside BMI.
Where a waist-to-height ratio calculator helps
Beyond BMI
See central fat that BMI alone can miss.
Tracking progress
Watch your waist change even when weight stays the same.
Simple target
Aim for a waist under half your height.
Family check
Works for children aged 5 and over too.
Check your BMI, estimate your body fat or see your ideal weight. This is general information, not medical advice. Talk to a doctor about your own health risks.
Waist-to-height ratio FAQ
What is a healthy waist-to-height ratio?
0.4 to 0.49, according to NICE. In practice, keep your waist to less than half your height.
How do I calculate my waist-to-height ratio?
Divide your waist measurement by your height, using the same units. A 34 in waist and 69 in height give 0.49.
Where should I measure my waist?
Midway between the bottom of your ribs and the top of your hips, after breathing out naturally.
Is waist-to-height ratio better than BMI?
It adds information BMI misses, because it reflects fat around the middle. NICE recommends using it together with BMI for adults with a BMI under 35.
Is it the same for men and women?
Yes. The NICE categories apply to both sexes and all ethnicities.
Can children use it?
Yes, NICE uses the same categories for children and young people aged 5 and over.