Free labs & hormones tool
HOMA-IR Calculator (Insulin Resistance Index)
HOMA-IR is fasting glucose in mg/dL times fasting insulin in µU/mL, divided by 405. With glucose in mmol/L, divide by 22.5 instead. A glucose of 90 mg/dL with an insulin of 10 µU/mL gives 2.2. There is no universal normal range: studies report different cutoffs, such as 1.85 to 3.46 in one Spanish population study.
Prepared by Prospyr · Reviewed October 3, 2026 · Free, no sign-up, runs in your browser
Plasma glucose after an overnight fast.
Most US labs report insulin in µIU/mL. Do not enter pmol/L here.
HOMA-IR
1.78
A higher value means more insulin was needed to hold that fasting glucose. There is no single cut-off that every lab and study agrees on.
Decision support only; it does not replace clinical judgment. HOMA-IR is a research index, not a diagnosis.
HOMA-IR cut-offs reported in studies
These are values one study reported for its own population and method. They are not a standard, and they will not fit every lab or every patient.
| Reported value | What it was | Your result |
|---|---|---|
| 1.85 | Cut-off in non-diabetic men, derived against metabolic syndrome criteriaGayoso-Diz 2013, 2,459 Spanish adults | Below |
| 2.05 | Threshold using metabolic syndrome components, whole sampleGayoso-Diz 2013 | Below |
| 3.46 | 90th percentile of the population distributionGayoso-Diz 2013 | Below |
HOMA-IR formula and units
Both versions give the same result. Pick the one that matches the glucose units on the report.
- Conventional units: HOMA-IR = glucose (mg/dL) × insulin (µU/mL) ÷ 405
- SI units: HOMA-IR = glucose (mmol/L) × insulin (µU/mL) ÷ 22.5
Both use fasting values. The constants 405 and 22.5 are linked by the glucose conversion: 405 ÷ 18.016 is about 22.5.
Worked examples
| Glucose | Insulin | Math | HOMA-IR |
|---|---|---|---|
| 90 mg/dL | 10 µU/mL | 90 × 10 ÷ 405 | 2.22 |
| 5.0 mmol/L | 10 µU/mL | 5.0 × 10 ÷ 22.5 | 2.22 |
| 100 mg/dL | 5 µU/mL | 100 × 5 ÷ 405 | 1.23 |
| 110 mg/dL | 15 µU/mL | 110 × 15 ÷ 405 | 4.07 |
HOMA-IR normal range: what studies report
Gayoso-Diz and colleagues studied 2,459 adults in a random Spanish sample (EPIRCE). They reported 3.46 as the 90th percentile of the population, 2.05 when the threshold was tied to metabolic syndrome components, and 1.85 in non-diabetic men. They also found the threshold in non-diabetic women changed with age. Their conclusion: there is great variability in the HOMA-IR threshold used to define insulin resistance.
That is why this page quotes cutoffs as reported in a study and does not label a result normal or abnormal. For a related lipid-based marker, see the cholesterol ratio calculator.
Limits of the index
HOMA-IR rests on one fasting glucose and one fasting insulin. Assay differences, short fasts and day-to-day variation all move it. The original model also describes beta-cell function, which this page does not calculate.
Practices that run metabolic or weight programs can keep fasting labs with the visit note in charting; the med spa software page shows the wider workflow.
Frequently asked questions
What is the HOMA-IR formula?
HOMA-IR = fasting glucose (mg/dL) × fasting insulin (µU/mL) ÷ 405. In SI units it is fasting glucose (mmol/L) × fasting insulin (µU/mL) ÷ 22.5. The approximation comes from Matthews and colleagues, Diabetologia, 1985.
What is a normal HOMA-IR range?
No single range is accepted everywhere. Gayoso-Diz and colleagues (2013) reported 1.85 in non-diabetic men and 2.05 across a Spanish adult sample when tied to metabolic syndrome components, and 3.46 as the 90th percentile of that population. Other populations and assays give other numbers, so use the cutoff your lab or protocol names.
How do I calculate HOMA-IR from mmol/L?
Multiply fasting glucose in mmol/L by fasting insulin in µU/mL and divide by 22.5. For 5.0 mmol/L and 10 µU/mL that is 50 ÷ 22.5 = 2.2, the same as 90 mg/dL with the 405 version.
Does insulin need to be in µU/mL?
Yes, for these two formulas. µU/mL is the same as mIU/L. If your report is in pmol/L, convert it to µU/mL first. This calculator does not accept pmol/L so that a wrong unit cannot slip through.
Is HOMA-IR a diagnosis of insulin resistance?
No. It is an index calculated from one fasting sample. Wallace, Levy and Matthews (2004) review its use and misuse and describe it as best suited to cohort and epidemiological work. This tool shows the number and quotes reported cutoffs; interpretation belongs to the treating provider.
Why does my HOMA-IR differ between labs?
Insulin assays are not standardized across labs, and a single fasting draw varies day to day. The formula itself is fixed, so differences usually come from the inputs.
Sources and scope
- Matthews DR et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia 1985;28:412-9
Peer-reviewed. The original HOMA model and approximation formula.
- Wallace TM, Levy JC, Matthews DR. Use and abuse of HOMA modeling. Diabetes Care 2004;27:1487-95
Peer-reviewed. Guidance on appropriate and inappropriate use of HOMA.
- Gayoso-Diz P et al. Insulin resistance (HOMA-IR) cut-off values and the metabolic syndrome in a general adult population. BMC Endocr Disord 2013;13:47
Peer-reviewed. Source of the 1.85, 2.05 and 3.46 values quoted in the table.
Decision support only; it does not replace clinical judgment. HOMA-IR is calculated as published; cutoffs are quoted from one study and are not a standard. The tool does not diagnose or recommend treatment.