Waist-to-Height Ratio Calculator — Keep Your Waist Under Half Your Height (2026)
Free waist-to-height ratio (WHtR) calculator. Enter your waist and height to see your ratio and risk band — a simple, research-backed check that often reads body shape better than BMI.
Your waist-to-height ratio is one of the simplest health checks there is: divide your waist by your height. Keeping it under 0.5 — waist less than half your height — is the target backed by decades of research.
How the waist-to-height ratio calculator works
The MyPlate.food Waist-to-Height Ratio Calculator divides your waist measurement by your height in the same unit, then reports the two-decimal ratio, the band it falls in, and the waist you need to stay under. Every step is arithmetic you can check by hand — no black box, no signup:
- Inputs required: your waist circumference and your height, in inches or centimeters. Nothing else — no age, no sex, no weight.
- The formula: WHtR = waist ÷ height, both in the same unit, rounded to two decimals. The units cancel, so inches and centimeters give the same ratio.
- Worked example: a 34 in waist at 5 ft 10 in (70 in) is 34 ÷ 70 = 0.49 — healthy, an inch under the 35 in target.
- The four bands: below 0.40 slim (take care), 0.40–0.50 healthy, 0.50–0.60 increased risk, 0.60 and above high risk — exactly 0.50 reads as increased. Those breakpoints match the central-adiposity categories in the UK's NICE guideline NG246.
- Your target waist: half your height, in the units you entered — 35 in for a 5 ft 10 in adult, 90 cm for someone 180 cm tall.
What is waist-to-height ratio?
Waist-to-height ratio (WHtR) is your waist circumference divided by your height, in the same units. Because central (belly) fat is the kind most tied to heart and metabolic risk, WHtR captures something BMI can miss: where you carry weight, not just how much you weigh.
One line covers everyone. The same 0.5 boundary applies to men and women and across ethnic groups, because dividing by height already adjusts for body size — that's what makes it a rule you can carry in your head. NICE applies its categories to anyone with a BMI under 35, including people with high muscle mass, the group BMI most often misreads.
How to measure your waist
The ratio is only as good as the tape, and placement matters more than tension. On a 5 ft 10 in frame, an inch of difference in where the tape sits moves the ratio by about 0.014 — enough to cross a band boundary if you're near 0.50.
- Stand up straight with your feet together. Don't suck in, and don't hold your breath.
- Wrap the tape midway between the bottom of your ribs and the top of your hip bones — for most people that lands at about navel level.
- Keep it horizontal the whole way around, against bare skin rather than over clothing.
- Snug, not tight: the tape should lie flat without denting the skin.
- Read it at the end of a normal breath out, then measure a second time and average the two.
- Measure your height without shoes — the calculator handles the unit conversion from there.
Your target waist, by height
The rule is waist under half your height — the table does the arithmetic for common heights, and the calculator gives your exact target in your own units.
| Height | Keep your waist under |
|---|---|
| 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) |
Half of each height — the 0.5 WHtR boundary, the same target the calculator reports.
Why it can beat BMI
BMI only knows your weight and height, so a stocky, muscular person and someone carrying abdominal fat can share a BMI. WHtR looks at the waist directly, so it flags central fat that BMI treats as invisible.
The evidence backs the swap. A systematic review and meta-analysis of 31 studies covering more than 300,000 adults (Ashwell, Gunn & Gibson, Obesity Reviews 2012) found waist-to-height ratio discriminated diabetes, high blood pressure, and cardiovascular risk better than either waist circumference or BMI.
It isn't a replacement for a full assessment — it's a fast, free screen you can repeat at home with a tape measure, and NICE uses it alongside BMI rather than instead of it.
If your ratio is 0.5 or above
A ratio at or above 0.50 is a prompt, not a diagnosis — NICE's advice at that point is to talk to a health professional. The number that has to move is your waist, and the gap is usually smaller than it feels:
- Do the subtraction: current waist − half your height = the inches to lose. At 5 ft 10 in with a 38 in waist, that's 3 in to reach the 35 in target.
- Losing 5–10% of body weight is the band clinical guidelines treat as meaningful, and waist circumference typically falls with it.
- Distribution and composition are different reads: this page measures where you carry fat, while the body fat calculator estimates how much of you is fat.
- For the eating side, the free MyPlate Plan calculator turns your age, sex, and activity into daily calorie and food-group targets in about two minutes.
Formula & sources
Waist-to-height ratio
Waist and height in the same unit, so the ratio is unitless. Healthy target below 0.5; bands break at 0.40, 0.50, and 0.60.
Sources
- Ashwell M, Hsieh SD (2005) Six reasons why the waist-to-height ratio is a rapid and effective global indicator for health risks. Int J Food Sci Nutr 56(5):303–307.
- Ashwell M, Gunn P, Gibson S (2012) Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis of 31 studies in more than 300,000 adults. Obes Rev 13(3):275–286.
- NICE (2025) Overweight and obesity management. NICE guideline NG246 — central adiposity by waist-to-height ratio: 0.4–0.49 healthy, 0.5–0.59 increased, 0.6 or more high, for people with a BMI under 35 kg/m².
Waist-to-height ratio FAQ
What is a healthy waist-to-height ratio?
Under 0.5 for most adults — your waist should measure less than half your height. This calculator reads 0.40–0.50 as healthy, 0.50–0.60 as increased risk, and 0.60 or above as high risk, the same breakpoints NICE guideline NG246 uses for central adiposity. The 0.5 line is identical for men and women.
How do I calculate my waist-to-height ratio?
Divide your waist measurement by your height, using the same unit for both. A 34 in waist at 5 ft 10 in (70 in) is 34 ÷ 70 = 0.49; an 80 cm waist at 180 cm is 80 ÷ 180 = 0.44. Because the units cancel, inches and centimeters give the identical ratio — the calculator on this page does the arithmetic and places the result in its band.
Is waist-to-height ratio better than BMI?
For spotting central fat, the evidence says yes. A meta-analysis of 31 studies covering more than 300,000 adults (Ashwell, Gunn & Gibson, Obesity Reviews 2012) found waist-to-height ratio discriminated diabetes, hypertension, and cardiovascular risk better than waist circumference or BMI. BMI still describes total weight relative to height, so the two answer different questions — NICE uses the ratio alongside BMI, not instead of it.
Where do I measure my waist?
Midway between the bottom of your ribs and the top of your hip bones — for most people that's about level with the navel. Keep the tape horizontal and snug without denting the skin, measure on bare skin after a normal breath out, and average two readings. An inch of drift in tape placement changes a 5 ft 10 in adult's ratio by about 0.014.
What should my waist be for my height?
Half your height, whatever that height is: 32 in at 5 ft 4 in, 35 in at 5 ft 10 in, 90 cm at 180 cm. The table above lists common heights, and the calculator reports your exact target in the units you entered.
Is a waist-to-height ratio of 0.5 healthy?
0.50 exactly is the first reading that is no longer healthy. This calculator, like NICE's central-adiposity categories, puts 0.50–0.60 in the increased-risk band and reserves healthy for ratios below 0.50. It's a borderline number rather than an alarm — at 5 ft 10 in, taking one inch off a 35 in waist brings 0.50 down to 0.49.
What is a good waist-to-height ratio for a woman?
The same as for a man: under 0.5. Unlike waist-to-hip ratio, which uses different cutoffs by sex, waist-to-height applies one boundary to everyone — NICE applies its healthy band to both sexes and all ethnicities. A woman who is 5 ft 4 in should keep her waist under 32 in, the same target a 5 ft 4 in man has.
Does waist-to-height ratio work for all ages?
It's used from childhood on: the NHS's own waist-to-height tool covers ages 5 and up, with under-18s measuring alongside a parent or carer, and the 0.5 boundary doesn't change with adult age. It isn't for everyone — the NHS excludes pregnancy, diagnosed or suspected eating disorders, and conditions that affect height, and NICE limits its categories to a BMI under 35. It's a general screen, not a diagnosis — pair it with your clinician's advice.