Estimated Average Glucose (eAG) Calculator

About the Estimated Average Glucose (eAG) Calculator

Estimated average glucose (eAG) translates an HbA1c percentage into a glucose number that is easier to compare with meter or lab readings. HbA1c reflects average glycemia over the previous 2–3 months, while eAG expresses that same long-term signal in familiar glucose units.

The conversion used here comes from the ADAG study equation: eAG (mg/dL) = 28.7 × A1c − 46.7. This page converts in both directions between HbA1c and eAG, shows the result in mg/dL and mmol/L, and places the value next to broad diagnostic threshold bands.

The result is a translation aid, not a substitute for diagnosis or treatment planning. HbA1c can read high or low in settings such as anemia, hemoglobin variants, kidney disease, pregnancy, or recent blood loss, so the number still needs clinical context.

When This Page Helps

HbA1c is easier to discuss when it is translated into a familiar glucose number. This calculator keeps the long-term average, the unit conversion, and the diabetes context together so patients and clinicians can compare A1c with meter readings, CGM summaries, and treatment targets more directly.

How to Use the Inputs

1. Select whether to convert from HbA1c to eAG or from average glucose to HbA1c.
2. Enter the HbA1c percentage or average glucose value.
3. Use presets for common A1c levels.
4. Optionally enter fasting glucose for additional diagnostic context.
5. Review the conversion results and the broad threshold bands.

Example Calculation

Tips & Best Practices

• A1c testing should be performed at least twice yearly in well-controlled diabetes, and quarterly if treatment has changed.
• A1c can be inaccurate in patients with hemoglobinopathies, altered red-cell turnover, or recent transfusion.
• Pregnancy, kidney disease, and some anemias can change how well HbA1c reflects actual glucose exposure.
• Use the converter as a communication aid, not as a replacement for the full diabetes workup.
• Meter averages and laboratory eAG can differ when testing patterns miss post-meal or overnight glucose swings.

Why eAG Is Useful

HbA1c is a strong long-term marker, but many people understand glucose values more easily than percentages. Translating A1c into eAG makes the result feel more concrete and helps show why a good-looking daily fingerstick log can still coexist with a higher A1c if post-meal spikes are frequent.

When eAG and Meter Averages Differ

A meter average depends on when the patient checks glucose. If readings are mostly fasting or pre-meal, the average can look better than the true 24-hour pattern. CGM data usually gives a closer match to eAG, especially when post-meal excursions and overnight values are captured.

Use With Clinical Context

A1c can be distorted by anemia, hemoglobin variants, recent transfusion, pregnancy, or other changes in red-cell turnover. When those factors are present, eAG is best treated as a communication aid rather than a substitute for the broader glycemic picture.

Frequently Asked Questions

• What does eAG represent?

  eAG is the estimated average blood glucose based on HbA1c. It represents the average glucose concentration over the previous 2–3 months, weighted toward more recent weeks.

• Is eAG the same as my fasting glucose?

  No. Fasting glucose is a single point-in-time measurement, while eAG reflects the average of all glucose levels (fasting and post-meal) over months. eAG is typically higher than fasting glucose.

• Why might my eAG not match my meter average?

  Self-monitoring often captures fasting or pre-meal values, which are lower than the true 24-hour average. Post-meal spikes and overnight values are frequently missed, leading to a lower meter average than eAG.

• Can conditions other than diabetes affect A1c?

  Yes. Hemolytic anemia, iron deficiency, blood transfusions, hemoglobin variants (HbS, HbC), and pregnancy can all falsely raise or lower A1c independent of glucose control.

• Does this page diagnose diabetes?

  No. It converts HbA1c and average-glucose values and shows broad threshold ranges, but diagnosis still depends on the type of test, repeat confirmation when needed, symptoms, and clinical context.

• Is eAG the same as CGM metrics?

  No. eAG is a conversion from laboratory HbA1c. CGM metrics such as time in range or GMI come from a different data source and time window, so they should not be treated as interchangeable.