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Free HOMA-IR Calculator (Insulin Resistance)

Estimate insulin resistance from fasting glucose and fasting insulin using the HOMA-IR formula.

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HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is a widely used research and clinical formula estimating insulin resistance from a single fasting blood draw: HOMA-IR = (fasting glucose x fasting insulin) / 405 (mg/dL convention) or / 22.5 (mmol/L convention). This calculator is for general reference and educational purposes only — it is not a medical diagnosis. Consult a doctor for actual insulin resistance assessment.

How it works

Select your glucose unit (mg/dL or mmol/L), then enter fasting glucose and fasting insulin. The tool applies the corresponding divisor (405 for mg/dL, 22.5 for mmol/L) automatically.

  1. Enter glucose unit.
  2. Enter fasting glucose.
  3. Enter fasting insulin (µU/mL).
  4. Click Calculate to see your results.

Examples

Fasting glucose 90 mg/dL, fasting insulin 5 uU/mL

HOMA-IR = (90 x 5) / 405 = 1.11.

Who should use it

  • Research and clinical estimation of insulin resistance from routine labs.
  • Tracking a fasting insulin-resistance marker over time alongside a doctor.

Industry applications

  • Endocrinology and metabolic research
  • Primary care metabolic screening

Advantages

  • Requires only a single fasting blood draw, unlike more involved clamp-based insulin sensitivity tests.
  • Widely used and cited across decades of research literature.

Limitations

  • Less precise than the hyperinsulinemic-euglycemic clamp, the research gold standard.
  • Reference ranges vary by lab, assay, and population.

Common mistakes to avoid

  • Mixing up the mg/dL and mmol/L divisors, which produces a HOMA-IR value off by roughly 18x.
  • Using a non-fasting glucose or insulin value, which invalidates the HOMA-IR estimate.

Best practices

  • Only use fasting (typically 8-12 hour fast) glucose and insulin values for this calculation.

Tips

  • Track HOMA-IR trends over time using consistent fasting conditions and the same lab where possible.

Frequently asked questions

Yes, with no signup and no limit on how many calculations you run.
The original HOMA-IR formula was published using glucose in mg/dL (divisor 405). When glucose is measured in mmol/L, a divisor of 22.5 is commonly used instead to keep the result on the same scale.
Reference ranges vary by lab, population, and assay — lower values generally indicate greater insulin sensitivity. This tool reports the calculated value only; ask your doctor how to interpret it for your situation.
Matthews DR et al., "Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man", Diabetologia, 1985.

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