HOMA-IR Calculator

What Is a HOMA-IR Calculator?

A HOMA-IR calculator takes two numbers from a simple fasting blood test, your fasting glucose and your fasting insulin, and turns them into a single score that gives you a rough read on how well your body is responding to insulin. HOMA stands for Homeostatic Model Assessment, and IR stands for insulin resistance, so the score is really a shortcut way of asking: is your pancreas working harder than it should to keep your blood sugar in check?

This tool does the math for you the moment you type in your numbers. Enter your fasting glucose and fasting insulin from any lab report, in whichever units your lab used, and you'll get your HOMA-IR score, a plain-language explanation of what that score usually means, and a bonus QUICKI index calculated from the exact same values.

What Is Insulin Resistance, In Plain Words?

Insulin is the hormone your pancreas releases after you eat, and its job is to help sugar move out of your blood and into your cells for energy. When your cells start ignoring insulin's signal, a state called insulin resistance, your pancreas has to pump out more and more insulin just to get the same job done.

For a while, your body can keep up. Fasting glucose stays normal because insulin is working overtime behind the scenes. That's exactly the window HOMA-IR is built to catch, since it looks at both numbers together instead of glucose alone. A normal fasting glucose reading can still hide a high insulin level, and HOMA-IR is one of the simplest ways to spot that combination early, often years before blood sugar itself starts climbing.

The HOMA-IR Formula, Step By Step

The formula behind this calculator was published by Matthews and colleagues back in 1985, and it's stayed the standard reference formula in research and clinical practice ever since because it's cheap, quick, and needs just one blood draw.

• HOMA-IR = (Fasting Insulin in µIU/mL × Fasting Glucose in mg/dL) ÷ 405
• If your glucose is in mmol/L instead, swap the constant: HOMA-IR = (Fasting Insulin in µIU/mL × Fasting Glucose in mmol/L) ÷ 22.5
• Worked example: glucose 95 mg/dL and insulin 12 µIU/mL → (95 × 12) ÷ 405 = 2.81
• That result would land in the early insulin resistance band on the reference table below.

How To Use This HOMA-IR Calculator

Pull out your lab report and find two values: fasting glucose and fasting insulin, both taken from the same blood draw after fasting for at least 8 hours. Type the glucose number into the first box and pick the right unit, mg/dL or mmol/L, then do the same for insulin, choosing µIU/mL or pmol/L depending on how your lab reported it.

Your HOMA-IR score updates instantly as you type, no button needed. Below the result you'll see which reference band your score falls into, along with a short explanation of what that band usually means. If you've had this test more than once, click "Add this result to the log" after each calculation to build a running trend chart across multiple lab visits, which is often more useful than any single reading on its own.

Understanding Your HOMA-IR Score

There's no single universal cutoff for HOMA-IR, since normal ranges shift slightly depending on the lab, the population studied, and even ethnicity and body weight. That said, the bands used in this calculator reflect the ranges most commonly cited in research and patient education for adults.

A score under roughly 1.0 usually points to strong insulin sensitivity. Scores between about 1.0 and 1.9 generally fall in the normal range for most healthy adults. Once a score climbs past about 1.9, it's often flagged as early insulin resistance, and scores above roughly 2.9 are commonly described as significant insulin resistance, a pattern closely tied to prediabetes, type 2 diabetes risk, and metabolic syndrome. These numbers are a starting point for a conversation with a doctor, not a diagnosis on their own.

Advanced Feature: QUICKI and HOMA-%B

This calculator doesn't stop at HOMA-IR. Since QUICKI, the Quantitative Insulin Sensitivity Check Index, is built from the exact same two lab values, it's shown automatically as a cross-check. QUICKI runs on a much smaller numeric scale, generally between about 0.3 and 0.4, and moves in the opposite direction from HOMA-IR, a lower QUICKI means more resistance, not less.

You'll also see a HOMA-%B estimate, a rough gauge of how hard your pancreas's beta cells are working to produce insulin compared to a healthy reference point. It's a much less standardized number than HOMA-IR, so treat it as extra context rather than something to fixate on.

Advanced Feature: Trend Log With Chart Export

A single HOMA-IR reading is a snapshot. What actually matters for most people managing insulin resistance, PCOS, or prediabetes is the direction that number moves over months of diet, exercise, or medication changes. Every time you calculate a new score, click the log button to save it into a running table plotted on a line chart, with the early and significant resistance thresholds marked directly on the graph for quick visual reference.

The log tracks your average score, shows the gap between your first and most recent entry, and lets you export the whole thing as a CSV file to bring to your next doctor's appointment. Nothing in the log leaves your browser, it's not uploaded or stored anywhere on our servers.

Fasting Glucose vs Fasting Insulin: Why Both Matter

A standard fasting glucose test only tells half the story. Someone can have a completely normal fasting glucose number while their fasting insulin is quietly climbing higher and higher, because their pancreas is compensating hard behind the scenes. That's the exact blind spot HOMA-IR is built to close, by pairing the two values together instead of judging glucose in isolation.

This is one reason doctors sometimes order a fasting insulin test even when glucose and A1C both come back normal, especially for people with PCOS, a strong family history of type 2 diabetes, stubborn weight gain around the belly, or skin changes like acanthosis nigricans, a dark, velvety patch of skin often seen with insulin resistance.

Who Typically Uses a HOMA-IR Calculator

People with PCOS use this calculator often, since insulin resistance is a core driver of the condition for a large share of women diagnosed with it, and tracking HOMA-IR over time helps gauge whether diet, exercise, or medication like metformin is actually moving the needle. It's equally useful for anyone with prediabetes, a family history of type 2 diabetes, or metabolic syndrome who wants a clearer picture than glucose or A1C alone can offer.

Researchers and clinicians also lean on HOMA-IR heavily because it's far cheaper and faster than the gold-standard hyperinsulinemic-euglycemic clamp test, which requires hours of IV monitoring in a clinical setting. HOMA-IR trades a little precision for something that only needs one simple blood draw, which is exactly why it became the standard research and clinical shortcut worldwide.

Common Mistakes People Make With HOMA-IR

• Not fasting for a full 8 hours before the blood draw, which throws off both glucose and insulin readings and makes the score unreliable.
• Mixing up units, entering a pmol/L insulin value as if it were µIU/mL will produce a wildly inflated, meaningless score.
• Treating one HOMA-IR result as a final diagnosis instead of one data point to discuss with a doctor.
• Comparing a HOMA-IR score directly against a friend's or a number found online without accounting for lab-to-lab differences in insulin assays.
• Ignoring the trend over time in favor of obsessing over a single number, when the direction of change usually matters more than any one reading.

A Short History of the HOMA Model

HOMA-IR came out of Oxford in 1985, when David Matthews and his research team were looking for a simpler alternative to the euglycemic clamp technique, the gold standard for measuring insulin resistance but far too slow, invasive, and expensive for routine clinical use or large studies. They built a mathematical model that used just fasting glucose and fasting insulin, values already collected in millions of routine blood tests, to approximate what the clamp test would show.

Since then, HOMA-IR has been used in thousands of published studies covering diabetes, PCOS, obesity, cardiovascular risk, and metabolic syndrome. It's not perfect, and it's been refined and debated over the decades, but it remains the most widely used insulin resistance estimate in both research and everyday clinical practice because it only needs a single fasting blood draw.

A Quick Note On Accuracy

HOMA-IR is a well-established estimate, not a perfect measurement. Because it depends on fasting insulin, and insulin assays can vary noticeably between labs, the exact same blood sample can occasionally produce a slightly different HOMA-IR score depending on where it was tested. This is one reason there's no single universal cutoff number used everywhere.

This calculator is built for education and personal tracking, not diagnosis. Always review your actual HOMA-IR result, and any trend across repeat tests, with a doctor who can weigh it alongside your full health picture, including weight, family history, other lab values, and symptoms.