HOMA-IR Calculator for Insulin Resistance Calculator

HOMA-IR Calculator for Insulin Resistance Calculator for Endocrinology. There is no single universal cutoff; thresholds are population- and assay-specific, which is why HOMA-IR is best read against a locally validated reference. A value near 1.0 represents the lean insulin-sensitive reference. In many non-diabetic Western and Asian cohorts, values above roughly 2.0 to 2.9 flag insulin resistance, with the upper-quartile boundary often cited around 2.5. Rising values track metabolic-syndrome burden, hepatic steatosis, and future type 2 diabetes risk. Because insulin assays are not standardized, act on the trend and on your lab's reference distribution rather than treating any printed cutoff as absolute.

How this calculator works

HOMA-IR estimates hepatic insulin resistance from a single fasting blood draw using the product of fasting glucose and fasting insulin, scaled by a constant. In conventional units the formula is (fasting insulin in uU/mL x fasting glucose in mg/dL) / 405; in SI units it is (fasting insulin in uU/mL x fasting glucose in mmol/L) / 22.5, where 22.5 is the normalizing product for a lean reference subject (insulin 5 uU/mL, glucose 4.5 mmol/L, giving HOMA-IR = 1.0). The value rises as either fasting glucose or insulin climbs, reflecting the compensatory hyperinsulinemia that accompanies peripheral and hepatic resistance. This is the 1985 approximation formula, not the later computerized HOMA2 model, which better handles higher glucose ranges and can accept C-peptide.

When to use this calculator

Use HOMA-IR as a research and screening surrogate for insulin sensitivity in non-diabetic and prediabetic adults, in epidemiological cohorts, PCOS and NAFLD workups, and metabolic-syndrome risk stratification when a hyperinsulinemic-euglycemic clamp is impractical. It correlates well with clamp-derived resistance (Rs about 0.88 in the original validation). Do not use it in established type 2 or type 1 diabetes with beta-cell failure, in patients on exogenous insulin or insulin secretagogues, during pregnancy, or when only a non-fasting sample is available; in overt hyperglycemia the linear approximation diverges from the true nonlinear model.

Inputs used

  • Fasting glucose
  • Fasting insulin
  • Unit system

Clinical interpretation

There is no single universal cutoff; thresholds are population- and assay-specific, which is why HOMA-IR is best read against a locally validated reference. A value near 1.0 represents the lean insulin-sensitive reference. In many non-diabetic Western and Asian cohorts, values above roughly 2.0 to 2.9 flag insulin resistance, with the upper-quartile boundary often cited around 2.5. Rising values track metabolic-syndrome burden, hepatic steatosis, and future type 2 diabetes risk. Because insulin assays are not standardized, act on the trend and on your lab's reference distribution rather than treating any printed cutoff as absolute.

Worked example

A 42-year-old with central obesity has fasting glucose 100 mg/dL and fasting insulin 18 uU/mL. HOMA-IR = (18 x 100) / 405 = 1800 / 405 = 4.44. In SI: glucose 100 mg/dL = 5.55 mmol/L, so (18 x 5.55) / 22.5 = 99.9 / 22.5 = 4.44. A value of 4.44 sits well above common insulin-resistance thresholds (roughly 2.0 to 2.9 depending on the population), signaling substantial resistance and warranting lifestyle intervention and cardiometabolic risk assessment.

Limitations and safety notes

HOMA-IR chiefly reflects hepatic (fasting) insulin resistance and underestimates the muscle-dominant resistance captured by dynamic testing. Its precision is modest, with a coefficient of variation around 31 percent in the original work, so single values are noisy and duplicate or triplicate sampling is preferred. Lack of insulin-assay harmonization means cutoffs do not transfer between labs. It is invalid once beta-cell function fails (advanced type 2 and type 1 diabetes) and in anyone taking insulin or secretagogues, and it performs poorly at high fasting glucose where the 1985 linear formula diverges from the computerized HOMA2.

Frequently asked questions

What is a normal HOMA-IR value?

A HOMA-IR of about 1.0 corresponds to the lean insulin-sensitive reference subject. There is no universal cutoff for resistance, but many non-diabetic populations use a threshold in the 2.0 to 2.9 range. Always compare against your own laboratory's insulin-assay reference because insulin measurement is not standardized.

What is the difference between HOMA-IR and HOMA2?

HOMA-IR here is the original 1985 linear approximation from fasting glucose and insulin. HOMA2 is the updated computerized model that accounts for the nonlinear glucose-insulin relationship, handles higher glucose ranges, can use C-peptide, and also outputs percent beta-cell function and insulin sensitivity. For high glucose values or beta-cell assessment, prefer HOMA2.

Does HOMA-IR work in patients with diabetes?

Not reliably. Once beta-cell function fails, as in advanced type 2 or type 1 diabetes, the fasting insulin no longer reflects the compensatory response the model assumes. It is also invalid in patients on exogenous insulin or insulin secretagogues. It is best suited to non-diabetic and prediabetic individuals.

Why do I need a fasting sample?

The model assumes steady-state basal glucose and insulin concentrations set by a fasting feedback loop. A non-fasting or post-prandial sample violates that assumption and inflates the result. Draw glucose and insulin together after an overnight fast, ideally in duplicate given the roughly 30 percent variability.

References

  • 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. PMID: 3899825.
  • Wallace TM, Levy JC, Matthews DR. Use and abuse of HOMA modeling. Diabetes Care. 2004. PMID: 15161807.

Editorial review and citation methodology

Reviewed by the Quick Medical Calculator Editorial Team. Last reviewed: May 19, 2026. The review checks calculator inputs, intended population, interpretation, limitations, and source alignment.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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