A1c to Average Glucose Calculator
Convert HbA1c percentage to estimated average glucose (eAG) in mg/dL and mmol/L.
What is A1c to Average Glucose?
HbA1c reflects your average blood sugar over the past 2–3 months by measuring glycation of haemoglobin. The ADAG study (Nathan et al., 2008) gave clinicians a simple way to back-translate any A1c into an estimated average glucose number that patients can compare to daily meter readings.
How is it calculated?
eAG (mg/dL) = 28.7 × A1c − 46.7. Divide by 18.018 to convert to mmol/L. The relationship is approximately linear over the typical clinical range of 4–14%.
Frequently Asked Questions
- How accurate is the conversion?
- Within ±15 mg/dL for most patients; some conditions affect the relationship.
- Why doesn't eAG match my meter?
- Meters capture single moments; eAG is the average across all moments.
- Is HbA1c reliable in anaemia?
- Less so — discuss with your clinician.