A1C to eAG Calculator

Converts HbA1c percentage into estimated Average Glucose (eAG) using the formula derived from the ADAG (A1c-Derived Average Glucose) study.

Formula (mg/dL): eAG = (28.7 * A1C) - 46.7

Formula (mmol/L): eAG = (1.59 * A1C) - 2.59

Example: An A1C of 7.0% = (28.7 * 7) - 46.7 = 154 mg/dL.

Clinical Context

The ADAG study established a linear relationship between HbA1c and average blood glucose over the preceding 2-3 months. Note that eAG is a mathematical average; it does not reflect glycemic variability (Time in Range).

Common Mistake

Assuming a 7.0% A1c guarantees good health. An A1c of 7.0% can be achieved with steady sugars at 154 mg/dL, or violently fluctuating sugars swinging between 50 and 250 mg/dL. Always pair A1c with Time in Range data from a CGM.