Waist-to-Height Ratio Calculator

Waist-to-height ratio is waist circumference divided by height, both measured in the same unit. The units cancel, so the result is a plain number such as 0.46. It describes how large the waist is relative to overall body frame, which makes it a simple screening estimate for central adiposity, the fat stored around the abdomen. The widely quoted public-health message is to keep your waist to less than half your height.

WHtR equals waist circumference divided by height, with both numbers in the same unit (centimeters or inches). Worked example: a waist of 80 cm and a height of 175 cm gives 80 / 175 = 0.457, which sits in the healthy band because it is under 0.50. Because both measurements use the same unit, converting both to inches gives the identical ratio.

The UK National Institute for Health and Care Excellence (NICE) guideline NG246 classifies central adiposity from WHtR as follows: 0.40 to 0.49 is healthy central adiposity with no increased health risk; 0.50 to 0.59 is increased central adiposity with increased health risk; 0.60 or more is high central adiposity with further increased health risk. These boundaries apply to adults of both sexes and all ethnic backgrounds, and are intended for people with a BMI below 35.

The 0.5 boundary comes from the NICE evidence review, which found that study cut-offs for elevated risk clustered around 0.5 across ethnicities and sexes. NICE phrases it as a memorable rule: keep your waist to less than half your height. A ratio of exactly 0.50 falls in the increased band, since the healthy band tops out at 0.49. This calculator applies the boundary the same way.

The standard medical landmark is the midpoint between the bottom of the lowest rib you can feel and the top of the hip bone (the iliac crest), usually just above the navel. Stand relaxed with feet shoulder-width apart, keep the tape horizontal and snug without compressing the skin, and read the measurement at the end of a normal breath out. Take two or three readings and average them. Small shifts in tape position can move the reading by several centimeters, so always measure the same way when tracking change over time.

They measure different things, so one does not replace the other. BMI uses weight and height but cannot tell where fat is stored, so a muscular person can score as overweight while carrying little abdominal fat. WHtR focuses on central fat, which is more closely linked to cardiometabolic risk. NICE recommends using WHtR alongside BMI (for adults with a BMI below 35) rather than choosing one. For a plain BMI number, see our BMI calculator.

WHtR divides waist by height, while waist-to-hip ratio divides waist by hip circumference. WHR uses WHO thresholds of 0.90 for men and 0.85 for women; WHtR uses the single 0.50 boundary for everyone. Both screen for abdominal fat from different angles and are often used together. Our waist-to-hip ratio calculator covers WHR in detail.

Body fat percentage estimates the share of total body weight that is fat, using methods such as the US Navy tape formula, skinfold calipers, or BMI-based equations. WHtR is simpler: it only compares waist to height and says nothing about total fat mass. The two complement each other. Our body fat calculator estimates body fat percentage with three methods side by side.

All three use waist and height, but the maths differ. A Body Shape Index (ABSI) combines waist, height, and BMI in the Krakauer 2012 formula to produce a mortality-linked z-score. Body Roundness Index (BRI) models the body as an ellipse, following Thomas and colleagues (2013). WHtR is the plain ratio waist divided by height with the 0.50 rule. See our A Body Shape Index calculator and Body Roundness Index calculator for those metrics.

Multiply your height by 0.5 to get the NICE healthy ceiling. For example, at 175 cm the target ceiling is 87.5 cm, and at 170 cm it is 85 cm. This calculator shows your personal target and how far your current waist sits above or below it. Treat the target as an educational reference, not a medical prescription, and talk to a healthcare professional before acting on it.

No. Because WHtR divides two lengths, the units cancel as long as waist and height use the same unit. A waist of 32 inches with a height of 70 inches gives 0.457, identical to 81.28 cm over 177.8 cm. Use whichever unit your tape measure shows; this calculator converts internally and the ratio is unchanged.

Yes. The Tracker tab on this page stores each measurement (date, waist, height, ratio) in your own browser only, and nothing is uploaded anywhere. It shows the change since your first entry and since the previous one, so you can see trends. Re-measure at the same landmark, at a similar time of day, for comparable readings.

WHtR is a screening estimate, not medical advice. The NICE bands were developed for adults and are not calibrated for children, pregnancy, or conditions that change body shape. A single reading is only a screening snapshot. If your ratio is 0.50 or above, or you have any concern at all, talk to a doctor or registered dietitian rather than acting on the number alone.