Insulin Resistance Calculator

Q: What are the signs of insulin resistance?

Insulin resistance often has no clear symptoms early on. 4 When signs show up, they may include: Dark, velvety patches of skin on the neck, armpits, or groin (acanthosis nigricans) Extra weight around the belly Skin tags Feeling tired or sleepy after meals Strong sugar or carb cravings Irregular periods or trouble getting pregnant High triglycerides and low HDL cholesterol Many people find out only after a blood test.

Q: What is the gold standard test for insulin resistance?

The hyperinsulinemic-euglycemic clamp. 2 In this test, insulin and glucose are given through an IV for several hours while blood is checked often. It is very accurate but slow, costly, and only used in research. HOMA-IR was created as a quick, cheap stand-in, and its results track closely with the clamp. 1

Introduction

This Insulin Resistance Calculator finds your HOMA-IR score. HOMA-IR stands for Homeostatic Model Assessment of Insulin Resistance. It is a simple way to check how well your body responds to insulin.

You only need two lab numbers from the same fasting blood draw: your fasting insulin and your fasting glucose. Type them in and pick your units. The calculator works with µIU/mL or pmol/L for insulin, and mg/dL or mmol/L for glucose.

Insulin is the hormone that moves sugar from your blood into your cells. When your cells stop listening to insulin well, your body makes more of it. That is insulin resistance. A high HOMA-IR score can be an early sign of prediabetes, type 2 diabetes, PCOS, or fatty liver disease.⁴

Your result comes with a score, step-by-step math, a chart of your lab values, and a table comparing your score with cut-offs published for several adult populations. Use it to understand your labs better, then talk with your doctor about what the number means for you.

How to use our Insulin Resistance Calculator

Enter two numbers from the same fasting blood test: your fasting insulin and your fasting glucose. The calculator gives you your HOMA-IR score, tells you what it means, and shows the math step by step.

Fasting Insulin: Type the fasting insulin value from your lab report. Mayo Clinic Laboratories lists a normal range of 2.6 to 24.9 µIU/mL for fasting insulin.⁷ That is about 16 to 149 pmol/L.

Fasting Insulin Unit: Pick µIU/mL or pmol/L to match your lab report. If you switch units, the number you typed is converted for you.

Fasting Glucose: Type the fasting glucose value from the same blood draw. A normal result is about 70 to 99 mg/dL (3.9 to 5.5 mmol/L). A result of 100 to 125 mg/dL means prediabetes.⁴

Fasting Glucose Unit: Pick mg/dL or mmol/L to match your lab report. The value changes over to the new unit on its own.

Calculate: Click Calculate to see your HOMA-IR score, the step-by-step math, the lab value chart, and the cut-off table.

Reset: Click Reset to clear your numbers and go back to the sample values.

Both lab values must come from the same fasting sample, taken after at least 8 hours without food.³ HOMA-IR is not correct for non-fasting blood.

What Is Insulin Resistance?

Insulin is a hormone made by your pancreas. Its job is to move sugar (glucose) out of your blood and into your cells, where it is used for energy. Insulin resistance happens when your cells stop listening to insulin. To keep up, your pancreas makes more and more insulin. For a while this keeps blood sugar normal, but insulin levels climb higher and higher. Over time, this can lead to prediabetes, type 2 diabetes and fatty liver disease (NAFLD). Insulin resistance is also involved in causing PCOS.⁸

What Is HOMA-IR?

HOMA-IR stands for Homeostatic Model Assessment of Insulin Resistance. It is a simple score that estimates how well your body responds to insulin. It uses two numbers from one fasting blood test: your fasting insulin and your fasting glucose. A higher score means more insulin resistance. A lower score means your body handles insulin well.

The HOMA-IR Formula

There are two versions of the same formula. Which one you use depends on your glucose units:

US units: (Fasting insulin in µIU/mL × Fasting glucose in mg/dL) ÷ 405
SI units: (Fasting insulin in µIU/mL × Fasting glucose in mmol/L) ÷ 22.5

Both give the same answer. If your insulin is reported in pmol/L, divide it by 6 to get µIU/mL.

How to Read Your Score

Higher scores mean more insulin resistance. A study that set cut-offs for children notes that a cut-off of 2.5 is accepted for adults, and that values for children and teens had not been reported.⁹ Cutoffs are not the same for everyone: published cutoffs run from 1.55 in a Thai study and 1.7 in a Japanese one to 2.73 in a U.S. NHANES sample and 3.8 in a French one.¹⁰

Getting an Accurate Test

Both lab values must come from the same blood draw after fasting for at least 8 hours. Water is fine, but food, juice, and coffee with cream are not.³ A non-fasting sample will make the score wrong. Insulin levels can also bounce around day to day, so doctors often repeat the test before making decisions.

What Can Improve Insulin Resistance?

Insulin resistance can often be improved. Losing extra weight, moving more (both walking and strength training), sleeping enough, eating less added sugar and refined carbs, and adding fiber and protein all help cells respond to insulin again. Some people also need medicine, such as metformin. Talk with your doctor about what fits you.

This calculator is for learning and tracking only. It does not diagnose any condition. Always go over your lab results with a healthcare provider.

Formulas used

HOMA-IR (US units)

\text{HOMA-IR} = \frac{\text{Fasting Insulin}\ (\mu\text{IU/mL}) \times \text{Fasting Glucose}\ (\text{mg/dL})}{405}

HOMA-IR (SI units) ²

\text{HOMA-IR} = \frac{\text{Fasting Insulin}\ (\mu\text{IU/mL}) \times \text{Fasting Glucose}\ (\text{mmol/L})}{22.5}

Insulin unit conversion

\text{Insulin}\ (\mu\text{IU/mL}) = \frac{\text{Insulin}\ (\text{pmol/L})}{6}

Glucose unit conversion

\text{Glucose}\ (\text{mg/dL}) = \text{Glucose}\ (\text{mmol/L}) \times 18

Insulin as percent of upper normal limit

\text{Insulin \%} = \frac{\text{Insulin}\ (\mu\text{IU/mL})}{24.9} \times 100

Glucose as percent of upper normal limit

\text{Glucose \%} = \frac{\text{Glucose}\ (\text{mg/dL})}{100} \times 100

Frequently asked questions

Can you have insulin resistance with normal blood sugar?

Yes. This is very common. Your pancreas makes extra insulin to force sugar into your cells, so your glucose reading still looks normal. The high insulin is the clue. That is why HOMA-IR uses both numbers instead of glucose alone. A person can have a fasting glucose of 90 mg/dL and still score above 3.0 if insulin is high.

What are the signs of insulin resistance?

Insulin resistance often has no clear symptoms early on.⁴ When signs show up, they may include:

Dark, velvety patches of skin on the neck, armpits, or groin (acanthosis nigricans)
Extra weight around the belly
Skin tags
Feeling tired or sleepy after meals
Strong sugar or carb cravings
Irregular periods or trouble getting pregnant
High triglycerides and low HDL cholesterol

Many people find out only after a blood test.

What causes insulin resistance?

It builds up from a mix of things:

Extra fat stored in the belly, liver, and muscle
Not moving much during the day
Diets high in added sugar and refined carbs
Poor or short sleep
Long-term stress
Family history and genetics
Some medicines, like steroids
Conditions like PCOS and fatty liver

Age also plays a role, but habits matter more.

Does a high HOMA-IR mean I have diabetes?

No. HOMA-IR is not a diabetes test. It shows how hard your body is working to keep blood sugar normal. A high score means higher risk of prediabetes and type 2 diabetes later. Diabetes is diagnosed with fasting glucose, A1c, or an oral glucose tolerance test.⁵ Ask your doctor to run those if your score is high.

Is HOMA-IR accurate if you take insulin shots?

Not reliably. HOMA-IR assumes the insulin in your blood came from your own pancreas. Injected insulin does not pass through the liver the way your own insulin does, so the model's assumptions do not hold, and its use in people taking insulin still needs more study.² It is also unreliable in type 1 diabetes and in people with very little insulin production. Doctors use other tests for these cases.

How is HOMA-IR different from an A1c test?

They measure different things. A1c shows your average blood sugar over about 3 months.³ HOMA-IR shows how much insulin your body needs to keep sugar in range right now. HOMA-IR often turns abnormal years before A1c does, because high insulin hides rising sugar for a long time. Many doctors use both together.

What is the gold standard test for insulin resistance?

The hyperinsulinemic-euglycemic clamp.² In this test, insulin and glucose are given through an IV for several hours while blood is checked often. It is very accurate but slow, costly, and only used in research. HOMA-IR was created as a quick, cheap stand-in, and its results track closely with the clamp.¹

How long does it take to lower HOMA-IR?

Changes can show up fast. Fasting insulin drops within 2 to 8 weeks of regular exercise and better eating. Losing 5% to 10% of body weight often cuts HOMA-IR by a third or more. Most doctors retest after about 3 months so the change has time to settle in.

Can thin people have insulin resistance?

Yes. It is called being "metabolically obese, normal weight." Fat stored inside the liver and around organs drives insulin resistance even when body weight looks fine. Low muscle mass, poor sleep, and genetics add to it. People of South Asian, East Asian, and Hispanic background often show insulin resistance at lower body weights.

Why does my HOMA-IR change between tests?

Fasting insulin bounces around a lot and can vary noticeably from one day to the next. Stress, illness, poor sleep, a late meal the night before, and even the lab's insulin assay can shift the number. That is why one high score is not a diagnosis. Doctors usually repeat the test before acting on it.

Does PCOS cause insulin resistance?

They go together closely. Insulin resistance is found in about 75% of lean women with PCOS and 95% of those with a BMI over 25.⁸ High insulin pushes the ovaries to make more testosterone, which causes missed periods, acne, and extra hair growth. Lowering insulin with exercise, food changes, or metformin often helps PCOS symptoms too.

What can I check if my lab does not test fasting insulin?

Two simple stand-ins use tests most labs already run:

Triglyceride-to-HDL ratio: divide triglycerides by HDL. Above 3.0 (in mg/dL) suggests insulin resistance.⁶
TyG index: uses fasting triglycerides and fasting glucose.

Waist size also helps. These are rougher than HOMA-IR but still useful clues.

What is HOMA-B and how is it different from HOMA-IR?

Both come from the same two lab values. HOMA-IR estimates insulin resistance, meaning how well your cells respond. HOMA-B estimates beta cell function, meaning how much insulin your pancreas can still make.² In early insulin resistance, HOMA-IR and HOMA-B are both high. As type 2 diabetes sets in, HOMA-B falls because the pancreas wears out.

Do I need to stop medicines before a fasting insulin test?

Never stop a medicine on your own. Tell your doctor what you take, since steroids, some blood pressure pills, birth control, and diabetes drugs can shift insulin and glucose. Your doctor will say if anything should be paused. Also avoid hard exercise and alcohol the night before, and drink only water during the fast.

Sources

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