HOMA-IR Calculator
Estimate insulin resistance from a single fasting glucose and fasting insulin with the HOMA-IR index used widely in research and screening.
How it works
HOMA-IR = (fasting glucose [mg/dL] × fasting insulin [µU/mL]) ÷ 405 · (use ÷22.5 when glucose is in mmol/L)
HOMA-IR approximates insulin resistance from a single fasting blood draw by multiplying glucose and insulin and dividing by a constant, avoiding the elaborate clamp studies used in research. A higher value means the pancreas is secreting more insulin to keep glucose in check — the hallmark of resistance. Cut-offs are not universal and vary by population and assay, so the bands here are indicative; the index is most useful for tracking change over time in the same person.
Worked example
With fasting glucose 90 mg/dL and fasting insulin 8 µU/mL: (90 × 8) ÷ 405 = 720 ÷ 405 ≈ 1.78 — the normal range, below the ~2.0 level where early insulin resistance is often flagged.
Frequently asked questions
What HOMA-IR value means insulin resistance?
There is no single agreed threshold, but many studies flag values above roughly 2.0–2.9 as suggestive of insulin resistance. The right cut-off depends on the population and the insulin assay used.
Do I have to be fasting?
Yes. HOMA-IR assumes a steady fasting state — typically 8–12 hours without food. Non-fasting glucose and insulin make the result meaningless.
Why do formulas use 405 or 22.5?
They are the same equation in different units: divide by 405 when glucose is in mg/dL, or by 22.5 when glucose is in mmol/L. Both give the same HOMA-IR.
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Educational clinical estimate only — not a diagnosis, medical advice, or treatment. Scores are screening aids that must be interpreted by a qualified clinician alongside the full clinical picture. Never make care decisions from this tool alone.