HOMA-IR: the formula and what it tells you
HOMA-IR estimates insulin resistance from two numbers you probably already have on a lab report — and it is usually more informative than either of them alone.
Calculate your HOMA-IR
Enter fasting insulin and glucose from the same blood draw. Choose the glucose unit shown on your lab report.
Formula: fasting insulin × fasting glucose ÷ 405.
An estimate, not a diagnosis. Cut-points vary, and HOMA-IR is not interpreted in the usual way for people taking insulin. Read the limitations.
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The formula
HOMA-IR is fasting insulin in µIU/mL multiplied by fasting glucose in mg/dL, divided by 405. If your glucose is reported in mmol/L, multiply insulin by glucose and divide by 22.5 instead.
Both values must come from the same genuinely fasted blood draw — typically 8–12 hours. A non-fasting sample makes the result meaningless rather than merely imprecise.
What the number means
Below about 1.0 suggests good insulin sensitivity. Around 1.0 to 1.9 is a reasonable middle. Above roughly 2.0 suggests meaningful insulin resistance, and above 2.9 suggests substantial resistance — though exact cut-points vary between laboratories and populations.
Note how far below typical laboratory flagging this sits. Someone can have a HOMA-IR near 3 with every individual value reported as normal.
Why fasting insulin alone is often enough
HOMA-IR and fasting insulin track each other closely in people whose glucose is still normal, which is exactly the group where early detection matters. In that situation the extra arithmetic adds little.
HOMA-IR becomes more useful once glucose starts to rise, because it captures the combination — a system that is both working harder and starting to lose control is in a different position from one that is only working harder.
This dashboard calculates HOMA-IR automatically when you enter both values, and displays it for context rather than scoring it directly, to avoid double-counting the same physiology.
Limitations worth knowing
HOMA-IR is a steady-state estimate derived from a single moment. It does not capture post-meal dynamics, which is where dysfunction often appears first.
Insulin assays vary meaningfully between laboratories, so a trend within one lab is more reliable than a comparison across them.
It is not interpretable in the usual way for anyone taking exogenous insulin.
One result is only part of the picture.
The Longevity Score assessment brings available measurements together across eight systems, using the framework from 8 Dials of Longevity. HOMA-IR is shown for context, not scored separately.
Calculate your Longevity Score →Explore related topics
Fasting insulin — the early signal · How to lower fasting insulin · The metabolic dial
Frequently asked questions
How do you calculate HOMA-IR?
Fasting insulin in µIU/mL multiplied by fasting glucose in mg/dL, divided by 405 — or divided by 22.5 if glucose is reported in mmol/L. Both values must come from the same genuinely fasted draw, typically 8 to 12 hours.
What is a good HOMA-IR score?
Below about 1.0 suggests good insulin sensitivity, 1.0 to 1.9 is a reasonable middle, above roughly 2.0 suggests meaningful insulin resistance, and above 2.9 suggests substantial resistance — though exact cut-points vary between laboratories and populations.