Know your insulin resistance risk — no blood test needed
InResRisk uses your waist circumference and height to estimate your insulin resistance risk, based on indices validated across hundreds of thousands of people in peer-reviewed research.
Try InResRisk free →Why anthropometric screening matters
The clinical gold standard for insulin resistance — HOMA-IR, the Matsuda index, or a full glucose tolerance test — requires a blood draw, a lab, and a GP referral. Most people never get these tests until something is already wrong.
Meanwhile, research shows that waist-to-height ratio (WHtR) can identify insulin resistance risk from measurements you can take at home with a tape measure. A 2021 study in Scientific Reports found WHtR combined with sex predicted insulin resistance (Matsuda index) with an AUC of 0.765 in non-diabetic adults.[6] The message is remarkably simple: keep your waist circumference to less than half your height.
A landmark 2010 systematic review by Browning, Hsieh and Ashwell analysed 31 studies covering around 300,000 subjects and found WHtR outperformed BMI for cardiometabolic risk prediction (AUC 0.704 vs 0.671).[1] Ashwell's 2014 actuarial validation then established 0.4, 0.5, and 0.6 as the three meaningful boundary values.[2]
InResRisk calculates WHtR alongside two supporting indices — BRI (Body Roundness Index) and the Conicity Index — that together give a more complete picture of central adiposity than any single measure alone.
What InResRisk calculates
- WHtR (Waist-to-Height Ratio) — the primary metric, validated in 300,000+ people across 31 studies for cardiometabolic risk prediction [1]
- BRI (Body Roundness Index) — geometrically models the torso as an ellipse; sex-specific cutoffs (women ≥ 3.757, men ≥ 3.965) validated for metabolic syndrome in Brazilian adults [3]
- Conicity Index — adds weight to the calculation, modelling "apple shape" adiposity; derived by Valdez (1991) [5] and primarily validated for cardiovascular risk
- BMI — shown as familiar reference context; not used for risk categorisation
- Healthy waist ceiling — the maximum waist measurement for your height at the 0.5 WHtR threshold
- Live updates — results recalculate instantly as you move sliders, no button to press
- Imperial and metric units — switch between kg/cm and lbs/in at any time
Risk thresholds at a glance
WHtR — sex-universal
| Range | Zone | Risk interpretation |
|---|---|---|
| < 0.40 | Very lean | Very low central fat; extremely low body fat carries its own risks |
| 0.40 – 0.49 | Healthy | Low risk — the target range for most adults |
| 0.50 – 0.59 | Elevated | Elevated cardiometabolic and insulin resistance risk |
| ≥ 0.60 | High | Strongly associated with metabolic syndrome and T2DM |
BRI & CI — sex-specific cutoffs [3][5]
| Index | Women — Normal | Women — Elevated | Men — Normal | Men — Elevated |
|---|---|---|---|---|
| BRI | < 3.757 | ≥ 3.757 (AUC 0.833) | < 3.965 | ≥ 3.965 (AUC 0.906) |
| CI | < 1.285 | ≥ 1.285 | < 1.344 | ≥ 1.344 |
BMI — reference only (WHO standard, sex-universal)
| BMI range | Category |
|---|---|
| < 18.5 | Underweight |
| 18.5 – 24.9 | Normal |
| 25.0 – 29.9 | Overweight |
| ≥ 30.0 | Obese |
Important limitations
WHtR and the supporting indices screen — they do not diagnose. A fasting blood test (HOMA-IR or fasting glucose + insulin) is needed for a clinical diagnosis of insulin resistance. A normal result on this tool does not rule out insulin resistance, particularly in lean individuals with significant metabolic dysfunction.
The 0.5 WHtR threshold is a composite cardiometabolic threshold, not an IR-specific diagnostic cutoff. In obese-only cohorts (BMI > 30), research suggests the optimal cutoff shifts to around 0.65. BRI cutoffs are primarily validated in Brazilian and Chinese populations and are not yet settled into international consensus.
This tool does not account for factors that affect insulin resistance but are not reflected in anthropometry — including physical fitness, diet quality, sleep, genetics, or medications.
Who built this
InResRisk is a solo side project. I became interested in anthropometric screening after reading the Browning/Ashwell systematic review and realising how much predictive power sits in a simple tape measure — accessible to anyone, anywhere, at zero cost.
The tool runs entirely in your browser. No measurements are sent anywhere. No account required. No tracking beyond anonymous page analytics.
If InResRisk prompted you to book a blood test or take your waist measurement seriously, that's the whole point.
Try InResRisk →
Key references
- Browning LM, Hsieh SD, Ashwell M. A systematic review of waist-to-height ratio as a screening tool for the prediction of cardiovascular disease and diabetes. Obesity Reviews. 2010;11(3):165–178. PMID 20819243
- Ashwell M. Waist-to-height ratio as a screening tool for cardiovascular risk. Nutrition Today. 2014;49(2):63–67. PMC4800150
- Rodrigues AM et al. Sex-specific body roundness index cutpoints for metabolic syndrome in Brazilian adults. Scientific Reports. 2025. PMC12003638
- Murai J et al. Body roundness index and insulin sensitivity correlation in middle-aged cohorts. Metabolism. 2024. PMC10951619
- Valdez R. A simple model-based index of abdominal adiposity. J Clin Epidemiol. 1991;44(9):955–956. PMID 1890438
- Waist-to-height ratio and sex as independent predictors of insulin resistance in non-diabetic adults. Scientific Reports. 2021. PMC8050044