Your A1c, as an average blood sugar you can read.

Enter an A1c result or an average glucose. The dial shows the estimated average glucose in mg/dL and mmol/L, and where the number sits in the American Diabetes Association ranges.

4 5 6 8 10 12 14 5.7 6.5
%
mg/dL
mmol/L
Diabetes range6.5% or higher (ADA)

Estimated average glucose (eAG) = 28.7 × A1c − 46.7, from the ADAG study. mmol/L = mg/dL ÷ 18.016. Real averages vary from person to person at the same A1c. This is a conversion, not a diagnosis.

A1c ranges

Diagnostic categories from the ADA Standards of Care (ADA 2026). Treatment goals are set individually with your care team. En español.

CategoryA1cEstimated average glucose
Normal Below 5.7% Below 117 mg/dL (6.5 mmol/L)
Prediabetes 5.7% to 6.4% 117 to 137 mg/dL (6.5 to 7.6 mmol/L)
Diabetes 6.5% or higher 140 mg/dL or higher (7.8 mmol/L)

How the converter works

The ADAG study measured A1c against average glucose in several hundred people and produced a linear formula (Nathan 2008). The ADA uses the same formula in its own calculator (ADA eAG).

eAG (mg/dL) = 28.7 × A1c − 46.7

An estimate, not a reading: your meter will not match it day to day, because eAG is a long-term average (NIDDK). Our method.

Using a CGM?

Your sensor's mean glucose can be turned into a Glucose Management Indicator (GMI), an A1c-like estimate from CGM data (Bergenstal 2018).

GMI (%) = 3.31 + 0.02392 × mean glucose (mg/dL)

Open the GMI calculator.

Sources

  1. Nathan DM, Kuenen J, Borg R, Zheng H, Schoenfeld D, Heine RJ; A1c-Derived Average Glucose (ADAG) Study Group. Translating the A1C assay into estimated average glucose values. Diabetes Care. 2008;31(8):1473-1478. doi.org/10.2337/dc08-0545
  2. American Diabetes Association. eAG/A1C conversion calculator (professional.diabetes.org). professional.diabetes.org/glucose_calc
  3. American Diabetes Association Professional Practice Committee. 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes 2026. Diabetes Care. 2026;49(Suppl 1). doi.org/10.2337/dc26-S002
  4. Bergenstal RM, Beck RW, Close KL, et al. Glucose Management Indicator (GMI): a new term for estimating A1C from continuous glucose monitoring. Diabetes Care. 2018;41(11):2275-2280. doi.org/10.2337/dc18-1581
  5. National Institute of Diabetes and Digestive and Kidney Diseases (NIH). The A1C Test & Diabetes. www.niddk.nih.gov/health-information/diagnostic-tests/a1c-test

Written and maintained by the controla1clevels.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-25. Spotted an error? See About.