Medical AIHOMA-IR insulin resistance calculator
HOMA-IR is a simple fasting surrogate for insulin resistance derived by Matthews and colleagues in 1985. A healthy reference individual scores about 1; higher values suggest more insulin resistance. There is no single universal threshold: cutoffs vary with the insulin assay, population, age, and BMI, so the number is best read against your own laboratory's reference range and trended over time.
How to measure each input
- Fasting state
- Both samples must be drawn after an overnight fast (typically 8 to 12 hours). HOMA-IR is only valid for fasting, steady-state values, not post-meal or random samples.
- Fasting insulin
- Measured in uU/mL (numerically equal to mIU/L or mU/L). Insulin assays differ substantially between laboratories, which is the main reason cutoffs are not transferable.
- Fasting glucose
- Plasma glucose from the same draw. Enter mg/dL or mmol/L and select the matching unit; the calculator converts internally (mmol/L = mg/dL / 18).
Interpretation
| Band | Meaning |
|---|---|
| Around 1 or below (reference range) | Consistent with normal fasting insulin sensitivity in many populations (a healthy reference individual scores about 1). Interpret against your own laboratory's reference range. |
| Intermediate (interpret with caution) | An intermediate zone. Some studies treat values from about 2.0 to 2.5 as a threshold for insulin resistance, but this is assay- and population-dependent and not universally agreed. Read alongside BMI, waist, lipids, and glucose. |
| Suggestive of insulin resistance (population-dependent) | A value around or above 2.5 is the most commonly cited general-population cutoff suggesting insulin resistance, though thresholds are lower in some Asian cohorts (about 1.4 to 2.0) and vary by assay. Treat as a prompt for metabolic assessment, not a diagnosis. |
Pitfalls, exclusions and caveats
- There is no universal HOMA-IR cutoff. Reported thresholds for insulin resistance range roughly from 1.4 to 2.9 depending on the population, age, sex, BMI, and especially the insulin assay used. Always anchor to the reporting laboratory's reference interval.
- Insulin assays are not standardised, so the same sample can give different HOMA-IR values in different labs. Trends within one lab are more reliable than comparisons across labs.
- HOMA-IR is a fasting surrogate, not a direct measure. The reference standard is the hyperinsulinaemic-euglycaemic clamp; HOMA correlates with it but is less precise, particularly at the individual level.
- It is unreliable when fasting insulin secretion is abnormal: advanced beta-cell failure, type 1 diabetes, insulin therapy, or exogenous insulin make the estimate uninterpretable.
- It is a research and screening tool. Do not use a single HOMA-IR value to diagnose or exclude diabetes or metabolic syndrome on its own.
HOMA-IR (SI) = fasting insulin (mU/L) x fasting glucose (mmol/L) / 22.5. Equivalently, with glucose in mg/dL: HOMA-IR = fasting insulin (uU/mL) x fasting glucose (mg/dL) / 405. (405 = 22.5 x 18, since glucose mmol/L = mg/dL / 18.)HOMA was described by Matthews et al. (1985). The simple HOMA-IR approximation is reproduced here for education and is not affiliated with the original authors. The updated computer model HOMA2 gives slightly different values.
Frequently asked
What is a normal HOMA-IR?
A healthy reference individual scores about 1. Many general-population studies treat values around or above 2.0 to 2.5 as suggesting insulin resistance, but there is no universal cutoff: it depends on the insulin assay, the population (lower in some Asian cohorts), age, sex, and BMI. Use your own laboratory's reference range.
Why do different calculators or labs give different HOMA-IR values?
Insulin assays are not standardised and can differ by roughly a quarter between laboratories, and the glucose unit (mg/dL vs mmol/L) must match the formula. The same blood sample can therefore produce different HOMA-IR numbers in different settings, so trends within one lab are more meaningful than cross-lab comparisons.
Can HOMA-IR diagnose diabetes or insulin resistance by itself?
No. It is a fasting surrogate for research and screening. Diagnosis relies on glucose and HbA1c criteria and the broader clinical picture (weight, waist, lipids, blood pressure). HOMA-IR is also invalid when beta-cell function is abnormal or insulin is being given.
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