# What is my HOMA-IR?

Calculates insulin resistance (HOMA-IR) and beta-cell function (HOMA-%B) from fasting glucose and fasting insulin with the Matthews 1985 formulas, in US or SI units.

- Page: https://www.acalculator.org/health/homa-ir-calculator
- JSON spec: https://www.acalculator.org/health/homa-ir-calculator.json
- Version: 8e924341d24c

## Default answer

Example with the default inputs (Units US, Fasting glucose (mg/dL) 90, Fasting insulin (µU/mL) 10): Your HOMA-IR is 2.22.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| units | Units | US units (glucose mg/dL, insulin µU/mL) or SI units (glucose mmol/L, insulin pmol/L). |
| glucose | Fasting glucose (mg/dL) | Fasting plasma glucose, in mg/dL. |
| insulin | Fasting insulin (µU/mL) | Fasting insulin, in microunits per milliliter (the same number as mU/L). |
| glucoseSi | Fasting glucose (mmol/L) | Fasting plasma glucose, in mmol/L. |
| insulinSi | Fasting insulin (pmol/L) | Fasting insulin, in picomoles per liter. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| homaIr | HOMA-IR | Insulin resistance: glucose (mmol/L) × insulin (µU/mL) ÷ 22.5. 1.0 is the reference of the model. |
| homaB | HOMA-%B | Beta-cell function: 20 × insulin ÷ (glucose − 3.5), in percent of the reference. Only for glucose over 3.5 mmol/L. |
| glucoseOther | Glucose in the other unit | The glucose converted with 18 mg/dL per mmol/L. |

## Method

HOMA-IR = glucose (mmol/L) × insulin (µU/mL) ÷ 22.5 = glucose (mg/dL) × insulin (µU/mL) ÷ 405; HOMA-%B = 20 × insulin (µU/mL) ÷ (glucose (mmol/L) − 3.5).

## Assumptions

- Both values are fasting, from the same blood sample.
- Glucose mg/dL ÷ 18 = mmol/L (the factor behind the 405 constant); insulin pmol/L ÷ 6 = µU/mL.
- HOMA-%B is shown only when glucose is over 3.5 mmol/L (63 mg/dL).
- There is no single normal cut-off: it depends on the insulin assay and the population.

## Worked examples

1. units = si, glucoseSi = 4.5, insulinSi = 30 gives homaIr = 1, homaB = 100%. Source: Matthews et al., Diabetologia 1985: 4.5 × 5 ÷ 22.5 = 1 and 20 × 5 ÷ (4.5 − 3.5) = 100%.
2. units = us, glucose = 90, insulin = 10 gives homaIr = 2.222222, homaB = 133.333333%, glucoseOther = 5.0 mmol/L. Source: Matthews 1985: 90 × 10 ÷ 405 = 2.22.
3. units = us, glucose = 126, insulin = 25 gives homaIr = 7.777778, homaB = 142.857143%.
4. units = si, glucoseSi = 3.2, insulinSi = 12 gives homaIr = 0.284444, glucoseOther = 58 mg/dL.

## FAQ

### What is HOMA-IR?

HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) estimates how resistant the body is to insulin from one fasting glucose and one fasting insulin value. Matthews and others published it in 1985. A higher number means more insulin resistance.

### What is a normal HOMA-IR?

The model is scaled so that a healthy young adult scores about 1.0. There is no single accepted cut-off for insulin resistance: studies have used values from about 1.7 to 3.0, depending on the insulin test and the population. Your clinician reads the number with your other results.

### What is HOMA-%B?

HOMA-%B estimates how well the beta cells of the pancreas make insulin, as a percent of the reference (100%). It uses the same two values. The formula needs a glucose over 3.5 mmol/L (63 mg/dL).

### Does the insulin unit matter?

Yes. Insulin is reported in µU/mL (the same as mU/L) or in pmol/L. This page divides pmol/L by 6 to get µU/mL, the factor recommended for modern assays. Some older sources use 6.945, which gives a HOMA-IR about 14% lower.

### Is this the same as the HOMA2 calculator?

No. HOMA2 (1998) is a computer model that needs software. This page uses the simple 1985 formulas, which most papers still report.

## Sources

- Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985;28(7):412-419. https://doi.org/10.1007/BF00280883
- Knopp JL, Holder-Pearson L, Chase JG. Insulin units and conversion factors: a story of truth, boots, and faster half-truths. J Diabetes Sci Technol. 2019;13(3):597-600. https://doi.org/10.1177/1932296818805074
- Wallace TM, Levy JC, Matthews DR. Use and abuse of HOMA modeling. Diabetes Care. 2004;27(6):1487-1495. https://doi.org/10.2337/diacare.27.6.1487