A1C ↔ eAG converter

What eAG means

Your A1C is a percentage — the share of hemoglobin in your blood with glucose attached, reflecting roughly the past three months. Estimated average glucose (eAG) translates that percentage into the same units your glucose meter uses, so the number feels familiar. An A1C of 7.0%, for example, corresponds to an average glucose of about 154 mg/dL (8.6 mmol/L). Same information, different units.

The formula comes from the ADAG (A1C-Derived Average Glucose) study and is the one used in clinical practice: eAG in mg/dL = 28.7 × A1C − 46.7.

Why your lab A1C and meter average differ

If you compare the eAG from your lab A1C with the average shown on your glucose meter, they usually won't match — and that's expected. A meter average only reflects the moments you happen to test, which for many people skews toward fasting and pre-meal checks, when glucose tends to be lower. eAG reflects every hour of every day — overnight, after meals, and everything between finger sticks.

Individual differences also play a role: red blood cell lifespan, anemia, and other factors can nudge A1C up or down a little for the same average glucose. Neither number is wrong; they're two views of the same picture. Your healthcare provider can help you interpret both together.