HOMA-IR Calculator
What the HOMA-IR Calculator Does
This HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) calculator estimates how resistant your body may be to insulin using two fasting lab values: plasma glucose and insulin. It is designed for educational purposes only and cannot diagnose diabetes, prediabetes, or any medical condition. Always discuss your results with a qualified healthcare professional.
Insulin resistance is a key feature of conditions such as type 2 diabetes, metabolic syndrome, non-alcoholic fatty liver disease, and some forms of cardiovascular disease. A higher HOMA-IR value generally indicates higher estimated insulin resistance. Because the calculation is simple and only requires standard fasting labs, it is widely used in research and sometimes in clinical practice as a rough indicator of insulin sensitivity.
How HOMA-IR Is Calculated
This calculator uses the most common version of the HOMA-IR formula, which assumes that fasting glucose is reported in milligrams per deciliter (mg/dL) and fasting insulin is reported in micro-units per milliliter (µU/mL or mIU/L). Both measurements should be taken after an overnight fast of at least 8 hours, with only water allowed unless your clinician instructs otherwise.
The formula is:
HOMA-IR = (Fasting glucose in mg/dL × Fasting insulin in µU/mL) ÷ 405
In MathML form, this can be written as:
where G is fasting plasma glucose in mg/dL and I is fasting insulin in µU/mL. The constant 405 is a scaling factor that converts the units into an approximate index of insulin resistance.
Other variants of the HOMA model exist (for example, using glucose in mmol/L or using updated computer-based models such as HOMA2). This calculator specifically uses the original, widely cited formula above. If your lab reports glucose in mmol/L, you would need to convert to mg/dL (multiply mmol/L by 18) before using this calculator, or use a version of the formula adapted to mmol/L.
How to Enter Your Lab Values
- Fasting glucose (mg/dL): Use the value from a fasting blood test. Confirm that the unit on your report is mg/dL, not mmol/L.
- Fasting insulin (µU/mL): Use the fasting insulin value from the same blood draw if possible. It may be reported as µU/mL or mIU/L; these are typically used interchangeably in routine lab reports.
- Fasting conditions: Values should come from a blood sample taken after at least 8 hours without food or caloric drinks. Non-fasting values can make the HOMA-IR result misleading.
Enter both numbers into the calculator and select the button to compute your HOMA-IR score. The tool will display the numeric result and, optionally, a short description of how that value is often interpreted in research and clinical practice.
Typical Reference Ranges and Interpretation
There is no single universally accepted cut-off for HOMA-IR. Thresholds can vary by population, age, sex, ethnicity, and lab methods. However, many studies and clinicians use broad ranges like those summarized below for adults without diagnosed diabetes.
| HOMA-IR range (approximate) | Typical interpretation | Comments |
|---|---|---|
| < 1.0 | High insulin sensitivity | Often seen in lean individuals without metabolic risk factors, but can also appear in some people with impaired insulin secretion. |
| 1.0 – 2.0 | Borderline / mild insulin resistance | May indicate early changes in insulin sensitivity, especially if other risk factors (e.g., family history, elevated waist circumference) are present. |
| 2.0 – 2.5 | Moderate insulin resistance (common threshold) | Many studies consider values in this range to reflect clinically relevant insulin resistance in adults, though cut-offs differ. |
| > 2.5 – 3.0 | Marked insulin resistance | Often associated with higher risk of prediabetes, type 2 diabetes, or metabolic syndrome; should be interpreted only within full clinical context. |
| > 3.0 | Severe insulin resistance (in many studies) | Commonly seen in people with obesity, established type 2 diabetes, or other significant metabolic disturbances. |
These ranges are approximate and offered for general educational context. Different research groups and medical centers may define cut-offs differently. A value slightly above or below one of these categories does not automatically mean that you do or do not have a disease. Only your healthcare professional can interpret your results in light of your medical history, physical examination, additional lab tests, and any medications you take.
Worked Example Calculation
To see how the HOMA-IR calculation works in practice, consider a hypothetical fasting lab report for an adult patient:
- Fasting glucose: 95 mg/dL
- Fasting insulin: 10 µU/mL
Step-by-step calculation:
- Multiply fasting glucose by fasting insulin: 95 × 10 = 950.
- Divide by 405: 950 ÷ 405 ≈ 2.35.
In this example, the HOMA-IR value is approximately 2.35. Referring to the table above, this would fall in the moderate insulin resistance range in many studies. A clinician might take this as one sign of increased metabolic risk, especially if the person also has additional risk factors such as elevated waist circumference, high triglycerides, low HDL cholesterol, high blood pressure, or a strong family history of type 2 diabetes.
However, this single index is not enough on its own to make or rule out a diagnosis. A healthcare professional might order additional testing, review lifestyle habits, and consider individualized targets based on factors like age, ethnicity, and the presence of other conditions.
HOMA-IR Compared With Other Measures
HOMA-IR is one of several ways to assess insulin resistance and metabolic health. The table below contrasts it with a few other commonly used markers and tests.
| Measure | What it uses | What it reflects | Key advantages | Key limitations |
|---|---|---|---|---|
| HOMA-IR | Fasting glucose + fasting insulin | Estimated insulin resistance at fasting | Simple, inexpensive, widely used in research; can be calculated from routine labs. | Indirect estimate; less accurate in people with diabetes, very high glucose, or reduced insulin production. |
| Fasting plasma glucose | Single fasting glucose value | Baseline blood sugar control | Standardized, inexpensive, routinely available. | Does not directly show how hard the body is working (insulin levels) to keep glucose normal. |
| Hemoglobin A1c (HbA1c) | Average glucose over ~3 months | Long-term blood sugar control | Widely used for diagnosis of diabetes and prediabetes. | Influenced by conditions affecting red blood cells; does not show insulin levels or day-to-day variation. |
| Oral Glucose Tolerance Test (OGTT) | Glucose values before and after a glucose drink | How the body handles a glucose load | More sensitive than fasting glucose for some forms of impaired glucose tolerance. | Time-consuming, requires multiple blood draws; can be uncomfortable for some people. |
| Clamp studies (e.g., euglycemic clamp) | Controlled infusion of glucose and insulin in a research setting | Gold-standard measurement of insulin sensitivity | Highly precise and informative in research. | Complex, invasive, expensive; not used in routine clinical care. |
In routine practice, HOMA-IR is most often used as a supportive measure, not as a standalone test. Clinicians interpret it alongside other lab tests, medical history, and physical examination findings.
Factors That Can Influence HOMA-IR
Several lifestyle and medical factors can raise or lower your HOMA-IR score over time. These include, but are not limited to:
- Body weight and fat distribution: Excess body fat, particularly around the abdomen and internal organs (visceral fat), is strongly associated with higher insulin resistance.
- Physical activity: Regular aerobic and resistance exercise can improve insulin sensitivity and may reduce HOMA-IR values over weeks to months.
- Dietary pattern: Diets rich in minimally processed foods, fiber, and unsaturated fats and lower in added sugars and refined carbohydrates may improve insulin sensitivity in many people.
- Sleep and stress: Chronic sleep deprivation, sleep apnea, and high stress levels can worsen insulin resistance in some individuals.
- Medications and medical conditions: Certain drugs (such as some steroids or antipsychotics) and conditions (such as polycystic ovary syndrome, fatty liver disease, or endocrine disorders) can significantly affect insulin and glucose levels.
Any changes in these factors between lab tests can influence your HOMA-IR score. When monitoring trends, it is usually best to compare measurements taken under similar conditions (time of day, fasting duration, medication schedule, and overall health status).
Limitations and Assumptions of HOMA-IR
HOMA-IR is a useful approximate index, but it has important limitations that you should understand before using it to interpret your own lab results.
- Not a diagnostic test: HOMA-IR by itself does not diagnose diabetes, prediabetes, metabolic syndrome, or any other disease. Diagnosis relies on standardized criteria and must be made by a healthcare professional.
- Assumes stable fasting state: The formula assumes that your body is in a steady fasting condition. Eating, drinking caloric beverages, vigorous exercise, or acute illness shortly before the blood draw can distort the result.
- Less reliable in people with known diabetes: In individuals with established type 2 diabetes or significantly elevated glucose levels, beta-cell function (insulin production) may already be impaired. Under these conditions, a relatively low insulin level might produce a deceptively low HOMA-IR even when insulin resistance is high.
- Population differences: Typical HOMA-IR values and cut-offs differ by age, sex, ethnicity, and body composition. A result that is considered high in one group may be considered closer to average in another. Research studies often define their own thresholds based on the population being studied.
- Laboratory variability: Different labs may use different assays for insulin and glucose. Slight differences in measurement methods and reference ranges can affect your HOMA-IR value and how it is interpreted.
- Unit assumptions: This calculator assumes glucose is in mg/dL and insulin in µU/mL. Using mmol/L for glucose without conversion or entering non-fasting values will make the output misleading.
Because of these limitations, it is safest to treat HOMA-IR as an educational tool and a possible discussion point with your clinician rather than as a definitive measure of your health status.
When to Talk to a Healthcare Professional
You should seek guidance from a qualified healthcare professional if:
- Your HOMA-IR value is elevated compared with the approximate ranges above.
- You have symptoms such as increased thirst, frequent urination, unexplained weight change, fatigue, or blurred vision.
- You have risk factors like a family history of diabetes, high blood pressure, abnormal cholesterol, obesity, or polycystic ovary syndrome.
- You are already being treated for diabetes or prediabetes and are unsure how to interpret your numbers.
A clinician can explain what your result means in the context of your overall health, decide whether further testing is needed, and discuss possible lifestyle changes or treatments if appropriate.
Medical Disclaimer and References
This calculator and its explanatory content are provided for general informational and educational purposes only. They are not intended to offer medical advice, diagnose or treat any condition, or replace consultation with a licensed healthcare professional. Never ignore professional medical advice or delay seeking it because of information you obtain from this tool.
If you have questions about your blood test results, medications, or risk of diabetes or other conditions, speak directly with your doctor or another qualified health provider.
For further reading on HOMA-IR and insulin resistance, see for example:
- Matthews DR et al. "Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man." Diabetologia. 1985.
- American Diabetes Association. "Standards of Medical Care in Diabetes" (updated annually).
- Reputable endocrinology or diabetology textbooks and major medical organization guidelines.