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HOMA-IR Calculator

HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is a validated mathematical model that estimates insulin resistance from a single fasting blood draw. Developed by Matthews et al. in 1985, it remains the most widely used clinical and research tool for non-invasive insulin resistance assessment — requiring only two routine lab values: fasting glucose and fasting insulin. Insulin resistance underlies type 2 diabetes, metabolic syndrome, PCOS, non-alcoholic fatty liver disease, and is an independent cardiovascular risk factor. Knowing your HOMA-IR score is one of the most actionable metabolic health insights you can obtain.

Quick Answer

A HOMA-IR below 1.0 is optimal, 1.0–1.9 is normal, 2.0–2.9 suggests early insulin resistance, and ≥3.0 indicates significant insulin resistance. The formula is: (fasting glucose mg/dL × fasting insulin µIU/mL) / 405.

These results are estimates based on general formulas and are not a substitute for professional medical advice. Consult a healthcare provider before making health decisions.

Glucose Unit

Must be measured after 8–12 hours of fasting

Normal fasting insulin is typically 2–25 µIU/mL

Enter your fasting glucose and insulin values to calculate your HOMA-IR score.

How the Formula Works

  1. Obtain a fasting blood glucose value (8–12 hours without food). Values can be entered as mg/dL or mmol/L.

    If using mmol/L: glucose mg/dL = glucose mmol/L × 18.018

  2. Obtain a fasting serum insulin value from the same blood draw, measured in µIU/mL (also written mIU/L).

  3. Apply the Matthews HOMA-IR formula to estimate beta-cell secretion relative to insulin resistance.

    HOMA-IR = (Glucose mg/dL × Insulin µIU/mL) / 405

  4. Optionally calculate HOMA-B (beta-cell function percentage) to assess pancreatic reserve.

    HOMA-B = (360 × Insulin µIU/mL) / (Glucose mg/dL − 63) — only valid when glucose > 63 mg/dL

Methodology & Sources

Reviewed and updated April 5, 2026 · Prepared by GetHealthyCalculators Editorial Team

The HOMA model was derived from a mathematical model of glucose-insulin feedback in steady-state fasting conditions (Matthews et al., Diabetologia, 1985). The formula used here is the simplified linear HOMA1-IR equation. The updated HOMA2 model requires iterative computer calculation and uses slightly different reference values; HOMA1 is used here for transparency and reproducibility. HOMA-B estimates beta-cell function as a percentage of a normal reference (defined as HOMA-B = 100% at a fasting glucose of ~4.5 mmol/L and insulin of ~6 µIU/mL).

References

Limitations

  • HOMA-IR is derived from fasting steady-state values; it does not capture post-meal (postprandial) insulin dynamics.
  • Insulin assays are not standardised across laboratories — the same blood sample can produce different HOMA-IR values depending on the assay used.
  • The formula assumes linear beta-cell function and may be less accurate at very high glucose levels (>25 mmol/L / >450 mg/dL).
  • HOMA-IR is a screening tool, not a diagnostic test. Diagnosis of insulin resistance, pre-diabetes, or type 2 diabetes requires clinical evaluation.
  • Certain medications (corticosteroids, antipsychotics, diuretics) and conditions (liver disease, kidney disease) can alter HOMA-IR independent of true insulin sensitivity.

Frequently Asked Questions

What is a normal HOMA-IR score?
Most clinical studies and laboratories consider a HOMA-IR below 2.0 to be within the normal range. Scores below 1.0 reflect optimal insulin sensitivity. The precise cut-off for "insulin resistance" varies by study and population, but a threshold of 2.0–2.5 is widely cited in the literature. Always compare your result to your laboratory's specific reference range.
What is HOMA-B and what does it tell me?
HOMA-B estimates beta-cell function — the percentage of normal pancreatic insulin secretory capacity. A normal HOMA-B is approximately 100%. Values below 50% may suggest declining beta-cell reserve, which can precede or accompany type 2 diabetes. However, HOMA-B is less clinically validated than HOMA-IR and should be interpreted with caution.
What causes insulin resistance?
Insulin resistance is driven by a combination of genetic predisposition, excess body fat (particularly visceral and ectopic fat), physical inactivity, chronic sleep deprivation, high consumption of refined carbohydrates and ultra-processed foods, chronic stress, and certain medications. Aging is also associated with declining insulin sensitivity independent of body composition.
Can insulin resistance be reversed?
Yes, in many cases. Lifestyle interventions are highly effective: structured aerobic and resistance exercise can improve insulin sensitivity within weeks. A calorie-reduced diet — particularly one lower in refined carbohydrates — consistently reduces HOMA-IR scores. Weight loss of even 5–10% of body weight produces meaningful improvements. Adequate sleep and stress management also contribute. For some individuals, medical treatment (e.g., metformin) may be appropriate alongside lifestyle changes.
Do I need to fast before testing for HOMA-IR?
Yes. Both glucose and insulin must be measured in a true fasting state — typically 8–12 hours without caloric intake (water is fine). Eating before the test will elevate insulin and invalidate the result. The test is usually performed first thing in the morning.
How is HOMA-IR different from a glucose tolerance test?
A glucose tolerance test (OGTT) measures how your body handles a glucose load over 2 hours, providing a dynamic picture of glucose metabolism. HOMA-IR is a static snapshot from a single fasting blood draw. HOMA-IR is simpler, cheaper, and widely available, but the OGTT provides additional information about postprandial glucose handling that HOMA-IR cannot assess.
Why does glucose unit matter (mg/dL vs mmol/L)?
The original HOMA-IR formula was derived using glucose in mg/dL. If your lab reports glucose in mmol/L (common outside the US), it must be converted by multiplying by 18.018 before applying the formula. This calculator handles the conversion automatically — just select your unit.

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