The A1c  test is a blood test that provides information about a person’s average levels of blood glucose, also called blood sugar, over the previous 3 months. The A1c test is sometimes called the hemoglobin A1c, HbA1c, or glycohemoglobin test. The A1c test is the primary test used for diabetes management and diabetes research.
 
According to the Mayo Clinic, a normal A1c level can range from 4.5 to 6 percent for someone who does not have diabetes. On the other hand, someone who’s had uncontrolled diabetes for a long time might have an A1C level above 8 percent.

When the A1c test is used to diagnose diabetes, an A1c level of 6.5 percent or higher on two separate tests indicates you have diabetes. A result between 5.7 and 6.4 percent is considered prediabetes, which indicates a high risk of developing diabetes.

For most people who have previously diagnosed diabetes, an A1c  level of 7 percent or less is a common treatment target. But, remember, the higher your A1c level, the higher your risk of diabetes complications.

Here’s how the A1c level corresponds to average blood sugar level, in milligrams per deciliter (mg/dL) and millimoles per liter (mmol/L):

A1c level Estimated average blood sugar level
5 percent 97 mg/dL (5.4 mmol/L)
6 percent 126 mg/dL (7 mmol/L)
7 percent 154 mg/dL (8.5 mmol/L)
8 percent 183 mg/dL (10.2 mmol/L)
9 percent 212 mg/dL (11.8 mmol/L)
10 percent 240 mg/dL (13.3 mmol/L)
11 percent 269 mg/dL (14.9 mmol/L)
12 percent 298 mg/dL (16.5 mmol/L)
13 percent 326 mg/dL (18.1 mmol/L)
14 percent 355 mg/dL (19.7 mmol/L)