A1C to Average Glucose (eAG) Converter
Convert between A1C and estimated average glucose in either direction, in US and SI units. Useful when your lab report, your meter, and your prescriber all speak different units.
eAG = 28.7 × A1C − 46.7 (ADAG study regression, as used by NGSP and the ADA). A conversion, not a diagnosis — lab A1C and day-to-day meter readings measure different things over different windows.
How the conversion works
- eAG (mg/dL) = 28.7 × A1C − 46.7 — the regression from the ADAG study (Nathan et al., Diabetes Care 2008), which is the relationship the American Diabetes Association and NGSP use for reporting.
- mmol/L divides mg/dL by 18.016; IFCC mmol/mol = (A1C% − 2.15) × 10.929.
- A1C reflects roughly three months of average glucose. A single meter reading is a point in time — the two will rarely agree exactly, and this converter cannot diagnose anything.
Related: GLP-1s and metformin, GLP-1 eligibility criteria, and the full drug guides.