Estimated Average Glucose Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Metabolic measurements can look deceptively simple on a report. Estimated Average Glucose Calculator shows the arithmetic behind one specific interpretation without pretending to replace clinical context.

What this calculator does

HbA1c reflects longer-term glucose exposure, while daily glucose readings are usually expressed in mg/dL or mmol/L. This calculator converts an A1c percentage into an estimated average glucose, or eAG, to put the two measures on a more familiar scale. Metabolic calculations can add context to measurements, but laboratory timing, assay methods, medications, and the clinical situation can change what the result means.

How to use it

Enter or select Do you suffer from diabetes? and HbA1c. Use the units offered by the calculator and keep measurements consistent when you plan to compare results over time.

How the calculation works

The equation is eAG in mg/dL = 28.7 × HbA1c − 46.7. The calculator also converts the eAG result to mmol/L by dividing by 18.0182. The diabetes yes/no field is shown for context but does not change the equation.

Example

For the sample values prefilled in this calculator, the primary result is 111.1 mg/dL (Estimated average glucose), mmol/L is 6.17, and HbA1c is 5.5%. This example is there to show how the inputs flow through the implemented equation; replace the sample values with your own measurements before using the result.

How to interpret the result

eAG is a statistical estimate of the average glucose associated with a given A1c, not the arithmetic mean of your meter readings. It can help explain what an A1c result broadly corresponds to in everyday glucose units.

Limitations and notes

A1c can be misleading when red-cell lifespan is altered, such as with some anemias, hemoglobin variants, recent blood loss or transfusion, pregnancy, or certain kidney conditions. eAG also does not show glucose variability or episodes of hypoglycemia and hyperglycemia.