HOMA-IR Calculator
Estimate insulin resistance from a single fasting glucose and insulin measurement.
Works in both units
Accepts glucose in mg/dL or mmol/L and applies the correct divisor automatically.
A screening estimate
HOMA-IR is not a diagnosis. Interpret it with your lab's range and a clinician.
What is HOMA-IR?
Insulin resistance from one blood draw
HOMA-IR — the Homeostatic Model Assessment of Insulin Resistance — estimates how hard your body has to work to keep blood sugar in check. It was introduced by Matthews and colleagues in 1985 and uses just two fasting values: glucose and insulin. A higher number means more insulin resistance; a lower number means your cells respond well to insulin.
HOMA-IR multiplies fasting glucose by fasting insulin and divides by a constant that depends on the glucose unit.
HOMA-IR = (fasting glucose × fasting insulin) ÷ kThe divisor k is 405 when glucose is in mg/dL and 22.5 when glucose is in mmol/L. The two constants are chosen so both unit systems give the same answer for the same person. Insulin is in µU/mL (identical to mIU/L) either way.
Suppose a fasting blood test reports glucose 100 mg/dL and insulin 10 µU/mL.
Multiply the two fasting values
100 × 10 = 1,000.Divide by the mg/dL constant
1,000 ÷ 405 = 2.47.Read the band
2.47 falls in the 2.0–2.9 range, suggesting early insulin resistance.Confirm in context
Compare against your lab's reference range and discuss the trend with your doctor.
There is no single universal cut-off — the bands below are a common guide, and thresholds vary by laboratory, assay, and population.
Below 1.0
Good insulin sensitivity — cells respond efficiently to insulin.
1.0 – 2.9
Normal to early resistance — worth watching, especially with other risk factors.
2.9 and above
Significant insulin resistance — a reason to discuss further testing.
Because the cut-offs differ between sources, treat your number as a position on a scale rather than a pass/fail line. A trend over several tests is more informative than one reading.
A lower HOMA-IR is better — it means your pancreas does not have to over-secrete insulin to keep glucose normal. Fasting glucose can stay normal for years while insulin quietly climbs, so HOMA-IR can flag a problem earlier than glucose alone. Lifestyle changes that improve insulin sensitivity — losing excess weight, regular exercise, better sleep, and fewer refined carbohydrates — typically lower fasting insulin and therefore lower HOMA-IR over time. Track the direction of travel, not just a single value.
HOMA-IR is a model, and models have boundaries.
Not a diagnosis
HOMA-IR is a screening estimate, not a diagnostic test, and not medical advice. It is less reliable in people with very high glucose, on insulin therapy, or with impaired pancreatic function, where its assumptions break down. Reference ranges vary between laboratories. Diabetes and prediabetes are diagnosed with defined criteria such as HbA1c or a glucose tolerance test. Discuss your result, and any change in lifestyle or treatment, with a qualified healthcare professional.