Convert HbA1c to estimated average glucose (eAG) in mg/dL or mmol/L, or reverse-calculate HbA1c from average glucose with broad diabetes threshold context.
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.
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.
eAG (mg/dL) = 28.7 × HbA1c − 46.7. eAG (mmol/L) = eAG (mg/dL) ÷ 18.0182. Reverse: HbA1c = (eAG + 46.7) ÷ 28.7.
Result: eAG = 154 mg/dL (8.6 mmol/L). Diabetes, controlled.
HbA1c of 7.0% converts to eAG = 28.7 × 7.0 − 46.7 = 154 mg/dL. That gives a practical way to compare the laboratory HbA1c result with everyday glucose numbers.
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.
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.
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.
Last updated:
This page converts HbA1c to estimated average glucose with the ADAG equation and can also reverse that relationship to estimate HbA1c from an average glucose value. It reports the result in both mg/dL and mmol/L and places the output next to broad threshold bands for normal, prediabetes, and diabetes range.
The result is a translation aid, not a diagnosis or a treatment plan. HbA1c can read artificially high or low in settings such as anemia, hemoglobin variants, pregnancy, kidney disease, recent transfusion, or altered red-cell turnover, so the output should be interpreted with the broader diabetes workup.
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.
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.
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.
Yes. Hemolytic anemia, iron deficiency, blood transfusions, hemoglobin variants (HbS, HbC), and pregnancy can all falsely raise or lower A1c independent of glucose control.
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.
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.