Waist to Height Ratio Calculator guide
Divide your waist by your height to get a simple screen for belly fat and cardiometabolic risk, with the NICE bands and the new US Army pass mark shown side by side.
The formula: waist divided by height
Waist-to-height ratio (WHtR) = waist circumference ÷ height, both in the same unit. Inches or centimeters both work because the units cancel. The result is a plain number, usually between 0.4 and 0.7 for adults.
The public health message behind it is short: keep your waist to less than half your height. A 2012 systematic review and meta-analysis in Obesity Reviews (Ashwell, Gunn and Gibson; 31 studies, over 300,000 adults) found WHtR predicted diabetes, high blood pressure, and cardiovascular risk better than BMI or waist alone, with a boundary value of 0.5 for both men and women across ethnic groups.
The UK's NICE overweight and obesity guideline (NG246) now uses WHtR alongside BMI with three bands: 0.4-0.49 means no increased health risk, 0.5-0.59 increased risk, and 0.6 or more high risk. The calculator also flags results below 0.4, which may indicate low body weight.
How to measure your waist correctly
Stand relaxed, feet together, and breathe out normally. Wrap a flexible tape measure around your bare stomach at the level of your belly button (navel), keeping it level all the way around and snug without pressing into the skin. Read it at the end of a normal exhale. Do not suck in.
Some clinical protocols measure midway between the lowest rib and the top of the hip bone instead. The navel method is what the US Army uses and what most people can repeat reliably at home. Whichever you use, stick to it so results are comparable over time. Measure height without shoes, standing against a wall.
Worked example
Height 5'9" (69 in), waist 34 in: 34 ÷ 69 = 0.493. That is in the 0.4-0.49 band. To stay under 0.5, the waist should be below 34.5 inches.
Height 70 in, waist 39 in: 39 ÷ 70 = 0.557. That falls in the increased-risk band and does not meet the Army standard, which requires a waist under 0.55 × 70 = 38.5 inches.
The US Army waist-to-height standard (2026)
Army Directive 2026-13, effective July 7, 2026, replaced the Army's height and weight tables and the tape-test body fat estimate with waist-to-height ratio as the only Army Body Composition Program standard for the Regular Army, National Guard, and Reserve. Soldiers are measured at the navel, the waist is divided by height in inches, and the ratio must be less than 0.55. Assessments happen twice a year, and the tape test can no longer be used to challenge a WHtR result.
The Army said it would run a 180-day assessment of the new standard and adjust if needed, so check with your unit or the current directive before a record measurement. The calculator shows your Army limit (0.55 × height) as the waist you must stay under.
Common mistakes
Mixing units. A waist in inches divided by height in centimeters gives nonsense. Use the same unit for both.
Measuring at the jeans line. Many people wear pants below the navel, where the waist is often smaller. Measure at the belly button.
Pulling the tape tight or sucking in. It can shave off an inch or more and 0.02 from the ratio.
Using it during pregnancy. The bands do not apply.
Reading it as a diagnosis. A ratio of 0.55 may indicate more abdominal fat and higher risk. It does not mean you have diabetes or heart disease, and a ratio under 0.5 does not rule them out.
Why it beats BMI for some people
BMI cannot tell muscle from fat or show where fat sits. Fat stored around the organs (visceral fat) drives most of the metabolic risk, and waist size tracks it far better than weight. That is why a muscular person with a "high" BMI can have a healthy WHtR, and a person with a "normal" BMI can carry risky belly fat. NICE notes some groups, including people of South Asian, Chinese, Black African, and Middle Eastern backgrounds, develop cardiometabolic risk at lower BMIs, and WHtR's single 0.5 boundary works across ethnicities.
If your ratio is 0.6 or higher, or 0.5 or higher with other risk factors like high blood pressure or family history of diabetes, a check-up with blood pressure, blood sugar, and cholesterol tests is worthwhile.
How we calculate: sources
Frequently asked questions
What is a healthy waist-to-height ratio?
Below 0.5, meaning your waist is less than half your height. NICE classifies 0.4-0.49 as no increased risk, 0.5-0.59 as increased risk, and 0.6 or more as high risk.
How do I calculate waist-to-height ratio?
Divide your waist circumference by your height, using the same unit for both. A 34-inch waist at 69 inches tall gives 34 / 69 = 0.49.
Where should I measure my waist?
Around your bare stomach at the belly button, keeping the tape level and snug, at the end of a normal breath out. The US Army also measures at the navel.
What is the Army waist-to-height standard?
Since July 7, 2026, Army Directive 2026-13 requires soldiers to have a waist-to-height ratio below 0.55, measured at the navel, assessed twice a year. Check current rules with your unit.
Is waist-to-height ratio better than BMI?
For cardiometabolic risk, research suggests yes. A 2012 meta-analysis of over 300,000 adults found WHtR detected diabetes, hypertension, and heart risk better than BMI or waist alone.
Does the 0.5 boundary apply to everyone?
It applies to adults of both sexes and different ethnic groups. It does not apply during pregnancy, and children should be assessed by a clinician.
Is my data uploaded?
Everything runs in your browser. Nothing you enter is uploaded to a server or stored by us.
What waist size should I have for my height?
Less than half your height. At 5'6" (66 in) that is under 33 inches; at 6'0" (72 in), under 36 inches.