A1C Calculator
Estimated Average Glucose (mg/dL)
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Estimated Average Glucose (mmol/L)
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Understanding A1C and Average Blood Sugar
The A1C test (also called HbA1c or glycated hemoglobin) measures your average blood sugar level over the past 2-3 months. It reflects the percentage of hemoglobin proteins in your blood that are coated with sugar. The higher your blood sugar, the higher your A1C.
The conversion formula from A1C to estimated average glucose (eAG) is: eAG (mg/dL) = 28.7 x A1C - 46.7. This formula was established by the A1C-Derived Average Glucose (ADAG) study published in Diabetes Care.
Normal A1C is below 5.7%. Pre-diabetes is 5.7-6.4%. Diabetes is diagnosed at 6.5% or higher. For most diabetics, the ADA recommends an A1C target below 7%, though individual targets may vary.
Frequently Asked Questions
What is a normal A1C level?
Normal: below 5.7%. Pre-diabetes: 5.7-6.4%. Diabetes: 6.5% or higher. For people with diabetes, the general target is below 7%.
How is A1C converted to average blood sugar?
The formula is: eAG (mg/dL) = 28.7 x A1C - 46.7. For example, an A1C of 7% equals an average glucose of about 154 mg/dL.
How often should A1C be tested?
For people without diabetes, every 3 years after age 45. For diabetics, every 3-6 months depending on whether targets are being met.
Can A1C be inaccurate?
Yes. Conditions affecting red blood cells (anemia, sickle cell, recent blood loss or transfusion) can give false A1C results. Some ethnic groups may have naturally higher or lower A1C.