HOMA-B Calculator

Q: What does a low HOMA-B mean?

A HOMA-B below 100% suggests reduced beta-cell function, meaning the pancreas is producing less insulin than expected for the glucose level. This is common in progressive type 2 diabetes.

Q: How is HOMA-B different from HOMA-IR?

HOMA-B estimates how well the pancreas produces insulin (beta-cell function), while HOMA-IR estimates how well the body responds to it (insulin resistance).

Q: What is normal HOMA-B?

A normal HOMA-B is approximately 100–200%. Values below 50% indicate significant beta-cell dysfunction.

Estimates pancreatic beta-cell function from fasting plasma glucose and fasting serum insulin using the HOMA equation.

Endocrinology EndocrinologyEvidence-BasedUpdated 2026-08-06

Clinical decision-support tool for qualified healthcare professionals. Results are not a diagnosis and should not replace professional clinical judgment.

Clinical Notes

HOMA-B estimates pancreatic beta-cell function from fasting glucose and insulin. It models the expected insulin output for a given fasting glucose: for any glucose level, a higher fasting insulin implies greater beta-cell responsiveness, expressed here as (20 × insulin) / (glucose − 3.5) with glucose in mmol/L and insulin in µU/mL. The result is reported in percent units. The value is an indirect, fasting-based estimate of secretion, not a direct measurement of beta-cell mass or of the dynamic insulin response to a meal or glucose load. Because the index is computed relative to the prevailing fasting glucose, interpretation depends on the glucose level itself as well as on assay calibration and the fasting state. HOMA-B is not reliable in type 1 diabetes, in patients on exogenous insulin, or in acute illness, and it has limited comparability across populations and disease states. It should not be used as a standalone measure of beta-cell reserve; it is best paired with HOMA-IR and clinical evaluation to separate beta-cell dysfunction from insulin resistance.

Calculator Information

Specialty

Endocrinology

📋 Reference Ranges

Normal Range

100–200%

Reference ranges for this calculator
Classification	Range
Severe beta-cell dysfunction	<50.1
Reduced beta-cell function	50–100
Normal beta-cell function	100–200
Hyperinsulinemia	≥200

What This Calculator Measures

Estimates pancreatic beta-cell function relative to the prevailing fasting glucose, complementing HOMA-IR in the assessment of glucose–insulin homeostasis.

How to Use

Obtain fasting plasma glucose (mmol/L) and fasting serum insulin (µU/mL).
Enter both values.
Review the HOMA-B percentage against the reference ranges.
Interpret together with HOMA-IR to separate beta-cell dysfunction from insulin resistance.

How the Calculation Works

HOMA-B = (20 x fasting insulin) / (fasting glucose (mmol/L) - 3.5), an estimate of pancreatic beta-cell function.

Variables Explained

Fasting Glucose

Fasting plasma glucose in mmol/L, reduced by 3.5 in the denominator.

Fasting Insulin

Fasting serum insulin in microU/mL, multiplied by 20 in the numerator.

Interpretation Guide

HOMA-B of 100–200% is generally considered normal beta-cell function; 50–100% suggests reduced function; < 50% suggests significant beta-cell dysfunction; and ≥ 200% reflects hyperinsulinemia. Values must be interpreted in the context of the patient's fasting glucose and insulin.

Clinical Significance

HOMA-B provides a practical estimate of beta-cell function from routine fasting labs and helps track the progressive beta-cell decline characteristic of type 2 diabetes.

When It Is Useful

Estimating beta-cell function in type 2 diabetes
Research and longitudinal tracking of beta-cell decline
Pairing with HOMA-IR to characterize glucose handling

When It Is Not Useful

In type 1 diabetes or in patients on exogenous insulin
As a diagnostic test for diabetes
When the patient is not fasting
As a substitute for C-peptide when precise beta-cell assessment is needed

Common Mistakes

Entering fasting glucose in mg/dL for an equation that expects mmol/L and subtracts 3.5, which wrecks the result before it is even interpreted.
Interpreting a HOMA-B of 200% or higher as strong beta-cell reserve in a newly diagnosed patient when glucotoxicity can transiently inflate the value.
Substituting HOMA-B for C-peptide when a precise answer on beta-cell reserve is needed, since the index is only a fasting estimate of secretion.

Limitations

Requires fasting samples; non-fasting values are unreliable.
Insulin assay variability limits comparability across laboratories and studies.
May be transiently elevated in newly diagnosed type 2 diabetes due to glucotoxicity.
Not validated for type 1 diabetes or exogenous insulin use.
Is an estimate, not a direct measure of beta-cell mass.

Worked Example

A 50-year-old man with type 2 diabetes has a fasting glucose of 6.0 mmol/L and fasting insulin of 10 µU/mL.

Inputs:

glucose: 6.0

insulin: 10

Expected Result: HOMA-B = (20 × 10) / (6.0 − 3.5) = 80%, suggesting reduced beta-cell function (50–100% range).

Evidence & References

Source:: Endocrinology / Diabetes
Content updated:: 2026-08

Matthews DR, et al. Diabetologia. 1985;28(7):412-419.

References

Matthews DR, Hosker JP, Rudenski AS, et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985;28(7):412-419. (Original Description)

Frequently Asked Questions

What does a low HOMA-B mean?

A HOMA-B below 100% suggests reduced beta-cell function, meaning the pancreas is producing less insulin than expected for the glucose level. This is common in progressive type 2 diabetes.

How is HOMA-B different from HOMA-IR?

HOMA-B estimates how well the pancreas produces insulin (beta-cell function), while HOMA-IR estimates how well the body responds to it (insulin resistance).

What is normal HOMA-B?

A normal HOMA-B is approximately 100–200%. Values below 50% indicate significant beta-cell dysfunction.

Disclaimer: This calculator is intended for educational and research purposes only. HOMA-B is an estimate of beta-cell function and must not be used as a standalone diagnostic test.