HOMA-IR Calculator

HOMA-IR stands for Homeostasis Model Assessment of Insulin Resistance. It is a score worked out from fasting glucose and fasting insulin to estimate how well the body responds to insulin. It comes from a 1985 model of how the two balance each other when you have not eaten¹.

What HOMA-IR Measures

Insulin is the hormone that helps glucose move from the blood into cells. When cells respond less well, the body tends to need more insulin to keep glucose steady. A higher HOMA-IR means more insulin was present for the same glucose. It is a model estimate, not a direct measurement, and it does not diagnose anything.

The Formula

The original equation was published by Matthews and colleagues¹ and restated in a later guide by the same group². It uses glucose in mmol/L and insulin in µU/mL (the same number as mU/L). The 22.5 scales the score so that a normal young reference person scores 1.0². Because US lab reports use mg/dL, the equation is often written with 405 in place of 22.5 (22.5 x 18.016 = 405.4).

HOMA-IR = fasting glucose (mmol/L) x fasting insulin (µU/mL) / 22.5

HOMA-IR = fasting glucose (mg/dL) x fasting insulin (µU/mL) / 405 (rounded)

How This Calculator Computes Your Result

Enter fasting glucose in mg/dL or mmol/L and fasting insulin in µU/mL or pmol/L. The tool converts glucose to mmol/L (dividing mg/dL by 18.016) and insulin to µU/mL (dividing pmol/L by 6, the factor set by the WHO insulin standard), applies the 22.5 equation and rounds to two decimals. Because it works through mmol/L, it can differ from the 405 shortcut by up to 0.1%. If your report lists insulin in both units, enter the µU/mL number, since labs convert to pmol/L with different factors (6 or 6.945), which can change the score by about 15%. The tool also shows QUICKI, a second index from the same two numbers. It is not meant for people who take insulin.

What Your Result Means

There is no single cutoff for HOMA-IR. This tool puts your score in one of four zones built from the research reference points below. The zones show where a number sits. They do not say whether you have a condition.

Each research value below was set by a different study to answer a different question.

The 2.5 you often see online matches the value that worked best for metabolic syndrome in the Delhi adolescent study⁶. If your fasting glucose is 126 mg/dL (7.0 mmol/L) or higher, the tool hides the zone, because these studies analyze people with diabetes separately³.

Why There Is No Single Cutoff

A 2015 review found that HOMA-IR cutoffs differ across races, ages, genders and diseases¹⁰. In 2,459 Spanish adults, the metabolic syndrome cutoff was 1.85 in men but rose in women from 2.07 at age 50 to 2.47 at age 70³. The outcome matters too. The Czech study set 1.82 to separate prediabetes from normal glucose and 3.63 to separate diabetes from no diabetes⁵. Percentile cutoffs, like the NHANES 2.6, simply mark the top third of one sample⁴. The HOMA authors say that comparing populations needs the normal value for each population². The Czech authors concluded that HOMA-IR cannot be recommended as a reliable screening test⁵.

Fasting and Lab Differences

Fasting means nothing to eat or drink except water for at least 8 hours before the blood draw⁹. Both numbers must come from the same sample. Insulin results also depend on the lab. When 11 commercial insulin tests were compared, reported values differed about 2-fold, even though all were calibrated to the same reference⁷. The original HOMA was calibrated to an insulin test from the 1970s, so its scores can differ from those on today's tests². In the US NHANES survey the insulin test and lab changed between cycles, so researchers adjusted the values before comparing years⁴. Use your lab's own range if it prints one.

HOMA2 and QUICKI

HOMA2 is an updated computer model from the same Oxford group. It adds kidney glucose loss and non-linear effects, and the authors recommend it for absolute values rather than changes over time². This tool uses the original equation, not HOMA2.

QUICKI is 1 divided by (log of insulin plus log of glucose in mg/dL). It correlated with the clamp test at r = 0.78 in its first study⁸. It moves the opposite way to HOMA-IR: lower QUICKI means more resistance. This tool shows it as a number only, with no zones.