Waist-to-Height Ratio Calculator
Calculate your waist-to-height ratio (WHtR) from your waist and height measurements and see how it compares to the Ashwell WHtR Reference Bands and NICE Thresholds.
WHtR Relative to the Reference Boundaries
This bar is a visual reference showing your ratio against the 0.40 / 0.50 / 0.60 boundary values shared by both the Ashwell chart and NICE guidance — it is not a clinical risk scale.
Ashwell Waist-to-Height Ratio Reference Bands
NICE uses the 0.40, 0.50 and 0.60 thresholds for its central-adiposity classifications, but uses different terminology from the Ashwell chart. Its classifications are:
Waist-to-Height Ratio Calculator
Our Waist-to-Height Ratio (WHtR) Calculator works out the ratio between your waist circumference and your height and compares it to the Ashwell WHtR Reference Bands and NICE Thresholds. WHtR is a simple anthropometric measure used in research and public health assessment, alongside measures such as waist circumference and BMI, to help understand patterns of central body fat — and unlike waist-to-hip ratio, it uses the same reference thresholds for both sexes.
What Is Waist-to-Height Ratio?
Waist-to-height ratio is calculated by dividing your waist circumference by your height, using the same unit for both measurements. A higher ratio means your waist is proportionally larger relative to your height, reflecting a greater degree of central (abdominal) fat. Nutritionist Margaret Ashwell proposed a boundary value of 0.5 in 1996, later developed into a four-band reference chart. NICE uses the 0.40, 0.50 and 0.60 thresholds for its central-adiposity classifications, but uses different terminology from the Ashwell chart.
How to Measure Your Waist and Height
- Waist: Measure midway between your lowest rib and the top of your hip bone (iliac crest), keeping the tape horizontal and snug but not tight. Measure after breathing out normally.
- Height: Measure without shoes, standing upright with your back against a flat wall and your eyes level.
- Taking two or three measurements can help reduce measurement variation.
Ashwell Waist-to-Height Ratio Reference Bands
| WHtR Range | Ashwell Band |
|---|---|
| Below 0.40 | Take Care — may warrant checking overall body weight (WHtR alone cannot diagnose underweight; BMI and other clinical factors are needed) |
| 0.40 to below 0.50 | OK |
| 0.50 to below 0.60 | Consider Action |
| 0.60 or above | Take Action |
Source: Ashwell M. Charts Based on Body Mass Index and Waist-to-Height Ratio to Assess the Health Risks of Obesity: A Review. The Open Obesity Journal, 2011. These are population-level reference bands, not a diagnosis of any individual’s health status.
NICE Waist-to-Height Ratio Classifications
NICE guideline NG246 classifies the same WHtR boundaries using different terminology from the Ashwell chart:
| WHtR Range | NICE Classification |
|---|---|
| Below 0.40 | Not classified by NICE |
| 0.40 to 0.49 | Healthy central adiposity — no increased risk indicated by this WHtR classification |
| 0.50 to 0.59 | Increased central adiposity — increased health risk indicated by this classification |
| 0.60 or above | High central adiposity — further increased health risk indicated by this classification |
For adults, NICE recommends using waist-to-height ratio alongside BMI, particularly when BMI is below 35 kg/m². WHtR should not be used as a standalone measure of overall weight status. NICE uses the same WHtR thresholds for adults of both sexes and all ethnicities, including people with high muscle mass. NICE guideline NG246 does not cover pregnancy.
Source: NICE guideline NG246, Overweight and obesity management (last updated 8 January 2026).
How to Use This Calculator
- Choose your units – centimetres or inches.
- Enter your waist circumference – measured midway between your lowest rib and the top of your hip bone.
- Enter your height – measured without shoes.
- Click Calculate WHtR to see your ratio and which reference band it falls into.
WHtR vs BMI vs Waist-to-Hip Ratio
BMI is based only on height and weight, so it can’t tell you how fat is distributed around your body. Waist-to-hip ratio compares your waist to your hip circumference and uses different boundary values for men and women. WHtR compares your waist directly to your height and uses the same 0.50 threshold for both sexes, which several studies have suggested may make it a simpler screening measure than a BMI-and-waist-circumference matrix. Health professionals often consider WHtR alongside, rather than instead of, BMI and waist circumference.
Frequently Asked Questions
What is a healthy waist-to-height ratio?
The Ashwell chart places a WHtR of 0.40 to below 0.50 in the “OK” band, which NICE classifies as healthy central adiposity. A ratio below 0.40 falls in the Ashwell “Take Care” band, which may warrant checking overall body weight rather than indicating increased central-adiposity risk; NICE does not classify this range. These are population-level reference bands rather than individual diagnostic cut-offs, so they should be considered alongside other health indicators.
How do I measure my waist and height correctly?
Measure your waist midway between your lowest rib and the top of your hip bone (iliac crest), keeping the tape horizontal and snug but not tight, and measure after breathing out normally. Measure your height without shoes, standing upright against a flat wall. Taking two or three measurements can help reduce measurement variation.
Is waist-to-height ratio better than BMI?
WHtR and BMI measure different things. BMI estimates overall body weight relative to height, while WHtR estimates central fat relative to height. Because they capture different information, many health professionals consider both measures together rather than relying on either one alone. Some studies have suggested WHtR may be a simpler screening tool than combining BMI with waist circumference, since it uses one boundary value rather than sex-specific charts.
What does a high waist-to-height ratio mean?
A WHtR at or above the shared 0.50 boundary falls into the Ashwell “Consider Action” or “Take Action” bands, which NICE classifies as increased or high central adiposity. These are associated with a greater degree of central fat distribution in population studies. WHtR alone does not diagnose any condition. If you have concerns about your health, speak to your GP.
Does this apply to children or pregnant women?
NICE recommends the same WHtR thresholds for children and young people aged 5 years and over as for adults: 0.40–0.49, 0.50–0.59 and 0.60 or above, for both sexes and all ethnicities. NICE notes that the evidence for WHtR in children is less established than in adults, so it should complement rather than replace age-appropriate assessment. WHtR is not a reliable measure during pregnancy, when waist measurements change for reasons unrelated to fat distribution. In these cases, WHtR should be interpreted with caution or discussed with a healthcare professional.