A1C Calculator (HbA1c to Average Glucose)
Convert HbA1c to estimated average glucose (eAG) and back. Includes ADA diabetes management category - normal, prediabetes, diabetes.
HEALTHConvert HbA1c (glycated hemoglobin) percentage to estimated average glucose (eAG) in mg/dL or mmol/L and back, with ADA 2026 diabetes management category (normal, prediabetes, diabetes).
Uses the ADAG study formula: eAG = 28.7 × A1C - 46.7. A 1% rise in A1C corresponds to about 28.7 mg/dL higher average glucose. Categories: normal under 5.7, prediabetes 5.7-6.4, diabetes 6.5 or higher. Most adults target A1C under 7%; very stable patients aim for under 6.5%; older or complex patients under 8%.
A1C Calculator (HbA1c to Average Glucose)
Convert HbA1c percentage to estimated average glucose (eAG) and back. See your diabetes management category (normal, prediabetes, diabetes) per ADA 2026 guidelines.
ADA Target
Most adults: A1C < 7%. Very stable patients: < 6.5%. Older / complex patients: < 8%.
Understanding Your A1C
HbA1c (glycated hemoglobin) measures the percentage of your red blood cells that have glucose attached. Because red blood cells live about 120 days, A1C reflects average blood glucose over roughly the past 3 months. A 1% rise in A1C corresponds to about 28.7 mg/dL higher average glucose.
The conversion uses the ADAG study formula: eAG (mg/dL) = 28.7 × A1C - 46.7. So an A1C of 6.0% maps to an eAG of about 126 mg/dL; 7.0% to 154 mg/dL; 8.0% to 183 mg/dL. The ADA reclassifies the goals every few years; the < 7% target has held since 2013 for most adults with type 2 diabetes.
Continuous glucose monitor (CGM) data adds "Time in Range" (70-180 mg/dL): aim for over 70% of readings in range, with under 4% below 70 mg/dL. CGM time-in-range correlates strongly with A1C: 70% TIR ≈ A1C 7.0%, 50% TIR ≈ A1C 8.0%.
Educational tool only. A1C results depend on hemoglobin variants, anemia, recent transfusions, and lab calibration. Always interpret with your physician.