Convert A1C (percent) to estimated average glucose (eAG, mg/dL) and back, using the equation published by the American Diabetes Association and NIDDK.
Equation: eAG (mg/dL) = 28.7 x A1C - 46.7. Reverse: A1C (%) = (eAG + 46.7) / 28.7.
Estimated average glucose is an approximation that corresponds to A1C over the prior two to three months. It is not a single blood glucose reading.
A1C reflects average blood glucose over roughly the previous two to three months. The A1C-Derived Average Glucose (ADAG) study produced a simple linear formula that converts an A1C percentage into an estimated average glucose (eAG) in the same units as a meter reading.
For example, an A1C of 6.5 percent gives eAG = 28.7 x 6.5 - 46.7 = 139.85, which rounds to about 140 mg/dL.
The equation and the eAG concept come from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and the American Diabetes Association, based on the ADAG study by Nathan and colleagues (Diabetes Care, 2008). See NIDDK: The A1C Test and Diabetes and the American Diabetes Association: Understanding A1C.
The ADA describes general A1C categories: below 5.7 percent is in the normal range, 5.7 to 6.4 percent is prediabetes, and 6.5 percent or higher meets the threshold for diabetes. These are reference thresholds, not a diagnosis. Many factors, including certain anemias and pregnancy, can affect how A1C should be interpreted.
The American Diabetes Association and NIDDK use eAG (mg/dL) = 28.7 x A1C - 46.7, where A1C is the percentage. To go the other way, A1C (%) = (eAG + 46.7) / 28.7. This linear relationship comes from the A1C-Derived Average Glucose (ADAG) study.
No. eAG is an average over roughly the past two to three months that corresponds to your A1C. A single fingerstick reading at one moment can be much higher or lower.
The ADA defines an A1C of 6.5 percent or higher as diabetes, 5.7 to 6.4 percent as prediabetes, and below 5.7 percent as normal. These are general thresholds. Only a healthcare provider can interpret your result in context.
No. This tool only converts between A1C and estimated average glucose using a published equation. It does not diagnose, treat, or manage any condition. Talk to a qualified healthcare provider about your results.