HOMA-IR Calculator (HOMA1)
Calculate the original HOMA1-IR index from paired fasting insulin and glucose, with glucose-unit normalization, assay limitations and no universal diagnostic cutoff.
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Formula and medical content are based on the references listed on this page. See sources, About, and Sources and Review Process.
About
Formula
Interpretation
What HOMA1-IR estimates
HOMA1-IR is derived from basal fasting glucose and insulin as a steady-state surrogate, not a direct measurement of insulin sensitivity. Different glucose and insulin combinations can produce the same HOMA1-IR value.
Exact arithmetic and units
The formal paths are insulin × glucose (mg/dL) ÷ 405 and insulin × glucose (mmol/L) ÷ 22.5. They are equivalent after the exact glucose conversion. µU/mL and mIU/L are numerically equivalent. This page does not convert insulin from pmol/L, and rounds only the final display.
Fasting and sample requirements
Use insulin and glucose from the same paired fasting collection. Do not combine nonfasting or separately timed values. Acute illness, physiologic stress, recent food and medicines can alter the basal state; this page cannot verify collection quality.
No universal diagnostic cutoff
Proposed cutoffs vary with population, age, BMI, glucose state, study endpoint and insulin assay. Systematic assay differences mean a threshold from one laboratory or study cannot simply be transferred to another. This page provides no automatic category.
HOMA1, HOMA2 and reference methods
HOMA1 is the original linear approximation; HOMA2 is Oxford’s nonlinear computer model and the two are not interchangeable. Clamp studies, IVGTT and OGTT-derived dynamic indices answer different questions. This page does not simulate HOMA2, HOMA-%B or beta-cell function.
Clinical limitations
Exogenous insulin, type 1 diabetes or severe beta-cell failure, acute illness or physiologic stress, marked hypo- or hyperglycemia, pregnancy, childhood or adolescence, PCOS, medicines affecting glucose or insulin, kidney or liver disease, and insulin antibodies or assay cross-reactivity require condition-specific research or clinical pathways. This page neither diagnoses a condition nor selects treatment.
References
- 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(7):412–419. PMID 3899825. DOI 10.1007/BF00280883.
- Levy JC, Matthews DR, Hermans MP. Correct homeostasis model assessment (HOMA) evaluation uses the computer program. Diabetes Care. 1998;21(12):2191–2192. PMID 9839117. DOI 10.2337/diacare.21.12.2191.
- Wallace TM, Levy JC, Matthews DR. Use and abuse of HOMA modeling. Diabetes Care. 2004;27(6):1487–1495. PMID 15161807. DOI 10.2337/diacare.27.6.1487.
- Muniyappa R, Lee S, Chen H, Quon MJ. Current approaches for assessing insulin sensitivity and resistance in vivo: advantages, limitations, and appropriate usage. Am J Physiol Endocrinol Metab. 2008;294(1):E15–E26. PMID 17957034. DOI 10.1152/ajpendo.00645.2007.
- Sacks DB, et al. Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus. Diabetes Care. 2023;46(10):e151–e199. PMID 37471273. PMCID PMC10516260. DOI 10.2337/dci23-0036.
- Staten MA, et al.; Insulin Standardization Workgroup. Insulin assay standardization: leading to measures of insulin sensitivity and secretion for practical clinical care. Diabetes Care. 2010;33(1):205–206. PMID 20040676. PMCID PMC2797975. DOI 10.2337/dc09-1206.
- Matli B, et al. Distribution of HOMA-IR in a population-based cohort and proposal for reference intervals. Clin Chem Lab Med. 2021;59(11):1844–1851. PMID 34380182. DOI 10.1515/cclm-2021-0643.
- University of Oxford Diabetes Trials Unit. HOMA Calculator — Frequently Asked Questions.
FAQ
HOMA1-IR is a surrogate estimate derived from paired fasting insulin and glucose under basal steady-state assumptions. It is not a direct measurement of insulin sensitivity.
It uses fasting insulin × glucose ÷ 405 when glucose is in mg/dL, or fasting insulin × glucose ÷ 22.5 when glucose is in mmol/L. Both are the original linear HOMA1-IR equation.
Yes. Use paired values collected together during the same fasting assessment. Nonfasting or separately timed results should not be combined.
The page accepts µU/mL and mIU/L, which are numerically equivalent for insulin reporting. It does not automatically convert insulin from pmol/L because assay and activity-unit standardization affect comparability.
Glucose may be entered in mg/dL or mmol/L. The calculator normalizes the two units without rounding the internal value before calculating.
No. HOMA1 is the original linear approximation. HOMA2 is Oxford’s nonlinear computer model, so the two results are not interchangeable.
No. Proposed cutoffs vary with population, age, BMI, glucose state, insulin assay and study endpoint. This page does not assign a universal diagnostic category.
No. A HOMA1-IR value does not by itself diagnose insulin resistance, prediabetes, diabetes, metabolic syndrome or polycystic ovary syndrome.
Not with this implementation. Measured insulin may not reflect endogenous basal secretion, and assay cross-reactivity with insulin analogues varies.
Insulin assays are not fully harmonized and may produce systematically different values. A cutoff developed with one assay should not automatically be transferred to another.
The hyperinsulinemic-euglycemic clamp is a reference method for direct assessment. Clamp studies, IVGTT and OGTT-derived indices measure different physiologic responses and are not equivalent to HOMA1-IR.
Do not use nonfasting or unpaired results or a sample affected by exogenous insulin. Acute illness, pregnancy, childhood, severe beta-cell failure, marked hypo- or hyperglycemia, medicines and major kidney or liver disease require condition-specific interpretation.
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Disclaimer
Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.