How to Calculate HOMA-IR (Insulin Resistance)

Learn how to calculate HOMA-IR from fasting glucose and insulin values, what the result means, and how it compares to the QUICKI formula and range.

Free calculators used in this guide

HOMA-IR Calculator QUICKI Calculator Blood Sugar Converter

Overview

HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) estimates how well your body responds to insulin using two values from a single fasting blood draw. This article walks through the calculation and how to interpret the result.

This is an educational explanation, not medical advice. Discuss a high or low HOMA-IR score with a healthcare provider rather than treating it as a self-diagnosis.

What You Need

Fasting glucose, from a blood test taken after an 8 to 12 hour fast
Fasting insulin, from the same blood draw
Glucose measured in mmol/L and insulin in µIU/mL (the units the standard formula expects)

Steps

Get both values from the same fasting blood draw. Fasting glucose alone or fasting insulin alone isn't enough. HOMA-IR needs both from the same sample, since they get evaluated together.
Check your units. If your glucose result is in mg/dL, common in the US, rather than mmol/L, convert it first using the Blood Sugar Converter.
Multiply glucose (mmol/L) by insulin (µIU/mL). This gives you the numerator of the HOMA-IR formula.
Divide the result by 22.5. This constant normalises the score so a HOMA-IR of 1.0 represents a reference level of normal insulin sensitivity.
Use the HOMA-IR Calculator to skip the manual conversion and arithmetic. The HOMA-IR Calculator takes your fasting glucose and insulin values directly and returns the calculated score.
Cross-check with QUICKI for a second perspective. The QUICKI Calculator applies a different formula to the same two values, giving an independent estimate from the same blood draw.

Common Mistakes to Avoid

Using non-fasting values throws things off fastest: even a small amount of recent food intake can noticeably skew both glucose and insulin, invalidating the result. Mixing up units causes similar damage. Plugging in mg/dL glucose without converting to mmol/L first produces a HOMA-IR value roughly 18 times too high. And treating a single elevated score as a diagnosis goes too far in the other direction. HOMA-IR is a research and screening tool; diagnosing insulin resistance or diabetes requires clinical evaluation, often with repeated testing.

Formula & Methodology

HOMA-IR = (Fasting Glucose [mmol/L] × Fasting Insulin [µIU/mL]) ÷ 22.5

Worked example with fasting glucose of 5.5 mmol/L and fasting insulin of 8 µIU/mL:

HOMA-IR = (5.5 × 8) ÷ 22.5 = 44 ÷ 22.5 = 1.96

This falls within the commonly cited normal range, though your doctor's interpretation should always account for your full clinical picture.

For a fuller definition, see our glossary entry on HOMA-IR.

Frequently Asked Questions

What lab values do I need to calculate HOMA-IR?

You need fasting blood glucose and fasting insulin, both drawn from the same blood sample after an overnight fast, typically 8 to 12 hours. Non-fasting values will throw off the result. The [HOMA-IR Calculator](/homa-ir-calculator/) requires exactly these two values.

What is considered a normal HOMA-IR score?

A HOMA-IR score below 1.0 is often considered optimal insulin sensitivity, with values up to around 2.0 to 2.5 generally considered normal, though exact thresholds vary between labs and populations. Values well above this range suggest insulin resistance and are worth discussing with a doctor.

Why do glucose and insulin need to be measured in specific units for this formula?

The standard HOMA-IR formula expects glucose in mmol/L and insulin in µIU/mL. If your lab report uses mg/dL for glucose, which is common in the US, convert it first. The [Blood Sugar Converter](/blood-sugar-converter/) handles that conversion before you calculate HOMA-IR.

What's the difference between HOMA-IR and QUICKI?

Both use the same two fasting values, glucose and insulin, but QUICKI applies a logarithmic transformation that some research suggests correlates more consistently with directly measured insulin sensitivity. Running both the [QUICKI Calculator](/quicki-calculator/) and [HOMA-IR Calculator](/homa-ir-calculator/) from the same blood draw gives you two independent perspectives.

Can I calculate HOMA-IR from a home glucose meter reading instead of a lab test?

No, because HOMA-IR requires a fasting insulin value, and home glucose meters don't measure insulin. You need an actual lab blood draw that tests fasting glucose and fasting insulin together. A meter alone only ever covers half the equation.

How long do I need to fast before the blood draw for an accurate HOMA-IR?

Most labs require 8 to 12 hours of fasting, water is fine, before drawing blood for fasting glucose and insulin. Even a small amount of recent food intake can meaningfully raise both values. Follow your specific lab's instructions, since fasting requirements vary a little from one to the next.

Is HOMA-IR useful for people who don't have diabetes symptoms?

It can be. Insulin resistance often develops years before blood glucose itself becomes abnormal, so HOMA-IR can flag an elevated risk profile in people who feel fine and have normal standard glucose readings. That's why it's sometimes used as an early screening tool alongside other risk factors.

What other conditions can affect my HOMA-IR score besides diabetes risk?

Polycystic ovary syndrome (PCOS), obesity, and certain medications can all elevate HOMA-IR independent of diabetes risk, since insulin resistance is a broader metabolic marker rather than a diabetes-only indicator. Discuss any elevated result with a doctor who can weigh your full medical picture.

Can lifestyle changes lower my HOMA-IR score over time?

Weight loss, regular exercise, and dietary changes, particularly cutting back on refined carbohydrates, are commonly linked to improved insulin sensitivity and lower HOMA-IR scores on follow-up testing, though results vary by person. Retesting after a few months of sustained changes is a common way to track progress.

Why do some doctors use HOMA2-IR instead of the original HOMA-IR formula?

HOMA2-IR is a more refined, computer-modelled version that accounts for variations in hepatic and peripheral insulin resistance more precisely, but it needs specialised software rather than a simple manual calculation. The basic HOMA-IR formula covered here still sees wide use for general screening.

GUIDE

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