🧪 HOMA-IR Calculator
Assess insulin resistance using fasting plasma glucose and insulin according to the Homeostatic Model Assessment.
Use the lab value obtained after at least 8 hours of fasting. Switch units between mg/dL and mmol/L as needed.
Also known as fasting insulin concentration or immunoreactive insulin.
HOMA-IR (mg/dL) = (Glucose × Insulin) ÷ 405 • HOMA-IR (mmol/L) = (Glucose × Insulin) ÷ 22.5
How to Use This Calculator
Obtain fasting labs
Ask your laboratory for fasting glucose and fasting insulin measured on the same morning after at least 8 hours without food.
Enter values and unit
Type the glucose concentration and choose mg/dL or mmol/L. Enter the insulin level in µU/mL. Then press “Calculate HOMA-IR.”
Interpret with your clinician
Review the resulting index and category with your healthcare provider. Elevated values may prompt lifestyle interventions or additional testing.
Formula
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is derived from a mathematical model of beta-cell function and insulin-glucose homeostasis (Matthews et al., Diabetologia 1985). The simplified index uses fasting values:
- HOMA-IR = (Fasting Glucose (mg/dL) × Fasting Insulin (µU/mL)) ÷ 405
- HOMA-IR = (Fasting Glucose (mmol/L) × Fasting Insulin (µU/mL)) ÷ 22.5
Fasting glucose in mmol/L can be obtained by dividing mg/dL by 18.0182. Higher HOMA-IR indicates greater insulin resistance. Reference ranges vary with population, age, and assay calibration.
Full Description
Insulin resistance is a hallmark of metabolic syndrome, type 2 diabetes, and polycystic ovary syndrome. The HOMA-IR index provides a convenient approximation of insulin sensitivity using fasting labs, making it practical for epidemiologic studies and clinical screening.
Elevated HOMA-IR values often correlate with abdominal obesity, dyslipidemia, hypertension, and elevated inflammatory markers. Lifestyle modifications—weight loss, physical activity, and improved diet—can reduce HOMA-IR. Pharmacologic therapy (metformin, GLP-1 receptor agonists, TZDs) may be considered for persistent insulin resistance under medical supervision.
Remember that acute illness, steroid therapy, beta-cell failure, or type 1 diabetes alters fasting insulin and may render HOMA-IR less reliable. Additional measures like clamp studies or OGTT-derived indices provide deeper insights when warranted.
Frequently Asked Questions
What is a normal HOMA-IR value?
Values under 2.0 are often considered normal in adults, but cut-offs differ by laboratory, ethnicity, and age. Children and adolescents may have different thresholds.
Can I use capillary glucose instead of lab plasma glucose?
Laboratory plasma measurements are preferred. Home glucometer readings can vary and may not align with fasting insulin draws.
Does medication affect HOMA-IR?
Yes. Insulin therapy, steroids, beta-blockers, or weight-loss drugs can influence fasting glucose or insulin. Inform your clinician of all medications when interpreting results.
Is HOMA-IR valid for type 1 diabetes?
HOMA-IR assumes endogenous insulin production. It is not reliable in type 1 diabetes or advanced beta-cell failure where fasting insulin is very low.
How often should I repeat HOMA-IR?
Repeat testing every 3-12 months can help monitor response to lifestyle or pharmacologic interventions. Frequency should be guided by your healthcare provider.