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HbA1c to eAG Calculator

HbA1c to eAG Calculator

Convert a lab HbA1c percentage into the estimated average glucose (eAG) it represents, in mg/dL and mmol/L.

Formula

eAG (mg/dL) = 28.7 × HbA1c − 46.7. To express the result in mmol/L, divide by 18.0182.

Worked example

HbA1c 7.0% → 28.7 × 7.0 − 46.7 = 154 mg/dL (8.6 mmol/L).

Notes and limitations

  • The relationship is a population average (ADAG study); an individual’s mean glucose can differ.
  • Valid for NGSP-standardized HbA1c results between about 5% and 12%.
  • eAG is not a replacement for CGM time-in-range metrics.

Reference

Nathan DM et al. Translating the A1C assay into estimated average glucose values. Diabetes Care. 2008;31:1473-1478.

For clinics and DME suppliers

Turning calculations like this into a complete, compliant supply order – e-prescribe intake, documentation checks and prescriber signatures for diabetes supplies – is what Chatty ePrescribe does. This calculator stores nothing; the order workflow lives on the secure platform.