HOMA-IR calculator
Two numbers from a fasting blood test go in, one number comes out. This page shows the arithmetic and its source, and says nothing about you.
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Enter both numbers to see the arithmetic.
Both values must come from the same fasting sample, after 8–12 hours without food. A number worked out from two tests taken on different days is not a HOMA-IR.
This page does the arithmetic in your browser. The numbers you type are never sent anywhere: there is no server behind this form, and this page loads nothing from any other company.
What the guideline says about it
HOMA-IR is not recommended for routine use in PCOS (2023 guideline, 1.9.12). Discuss results with your clinician. The international guideline’s position is that measuring it does not change what is advised for an individual, and that the assays behind it are not standardised between laboratories — which is why the same blood can give different numbers in two labs, and why a threshold copied from an article may not apply to the lab that ran your test.
This calculator exists because people are handed these two numbers and want to know what the third one is. It is arithmetic, not an assessment.
The formula
Matthews and colleagues, Diabetologia 1985 — the paper that defined homeostasis model assessment:
HOMA-IR = fasting insulin (µIU/mL) × fasting glucose (mmol/L) ÷ 22.5
HOMA-IR = fasting insulin (µIU/mL) × fasting glucose (mg/dL) ÷ 405
The two forms are the same thing: 22.5 × 18.016 ≈ 405, where 18.016 converts mmol/L to mg/dL. For insulin, 1 µIU/mL = 6.0 pmol/L, the conversion this page uses.
What this page will not tell you
- Whether your number is high, low or fine. That depends on the laboratory’s own reference range, on the assay it used, and on everything else about you.
- What to do about it. That belongs to the clinician who ordered the test.
- Whether you have anything. A number is not a diagnosis, and this page does not make one.
Keeping the numbers
If you are collecting results over the years, Cycle Ally holds them with the laboratory’s own printed range, converts between units so results from different labs line up on one chart, and puts them in the summary you hand to your clinician. See what the app does.
Cycle Ally is a personal log. It does not diagnose, treat or prevent any condition and is not a substitute for professional medical advice. Not for contraception. Talk to your clinician before making health decisions.