A1C to eAG Converter
Turn an A1C percentage into an estimated average glucose (eAG) in mg/dL and mmol/L — or start from a glucose average and read it back as an A1C. Includes the ADA reference ranges and a printable conversion chart.
Your value
How to use this calculator
1. Pick which value you have
Use the "Convert from" toggle. Choose A1C (%) if you are reading a lab report, or Average glucose if you are starting from a meter or CGM average.
2. Enter the number and unit
A1C is entered as a percentage. Average glucose can be entered in mg/dL (common in the US) or mmol/L (common elsewhere) — switching the unit converts the number you already typed.
3. Read every form of the answer
The result box always shows all four values at once: the A1C, the eAG in mg/dL, the eAG in mmol/L, and which ADA reference range the A1C falls into.
4. Keep the chart
The conversion chart tab lists A1C from 5.0% to 14.0% in half-point steps with both glucose units. Download it as CSV or print it if you want a reference copy — then bring any questions to your clinician.
About A1C and estimated average glucose
What is eAG and how does it relate to A1C?
Estimated average glucose (eAG) restates an A1C percentage in the same units a glucose meter uses. The conversion is a straight line: eAG in mg/dL = 28.7 × A1C − 46.7, and mmol/L = mg/dL ÷ 18.0182. Because it is one formula, the same A1C always maps to the same eAG.
What are the ADA A1C ranges?
The American Diabetes Association describes an A1C below 5.7% as normal, 5.7% to 6.4% as the prediabetes range, and 6.5% or higher as the diabetes range. These are reference ranges for lab-measured A1C, not a diagnosis on their own.
Why doesn't my meter average match my eAG?
eAG is a statistical estimate derived from a research population, so an individual's true average can differ. Meter and CGM averages also depend on when readings were taken, and conditions affecting red blood cells can shift A1C itself. Differences are common and worth discussing with a clinician.