A normal A1C is below 5.7%, meaning your average blood sugar over the past two to three months has been in a healthy range. Once your A1C reaches 5.7% to 6.4%, you’re in the prediabetes range, and 6.5% or above indicates diabetes. If you already have diabetes, the general target is to keep your A1C below 7%, though your ideal number depends on your age, health, and life circumstances.
What the A1C Ranges Mean
The A1C test measures the percentage of your red blood cells that have sugar attached to them. Because red blood cells live for about two to three months, the test captures a rolling average of your blood sugar rather than a single snapshot. A higher percentage means your blood sugar has been running higher over that window.
The three diagnostic categories are straightforward:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
A diagnosis of diabetes based on A1C requires confirmation with a second test, unless you already have clear symptoms like excessive thirst, frequent urination, or unexplained weight loss. A single result of 5.8% or 6.0% doesn’t necessarily lock you into a prediabetes label, but it is a signal that your body is having more trouble managing blood sugar than it should.
A1C Targets If You Have Diabetes
The American Diabetes Association sets a general target of below 7% for most adults with diabetes. That number represents an estimated average blood sugar of about 154 mg/dL. Staying below 7% significantly lowers the risk of complications affecting the eyes, kidneys, and nerves.
How significant? In one study of 251 people with diabetes, those who lowered their A1C by about 1 percentage point through regular exercise reduced their risk of these small-vessel complications by 35%. That’s a meaningful payoff for each point you bring down.
Your personal target might be tighter or more relaxed than 7%. People who are younger, recently diagnosed, or otherwise healthy often aim lower, sometimes below 6.5%. On the other hand, people who have lived with diabetes for decades, who experience dangerous drops in blood sugar, or who have other serious health conditions may be better off with a target closer to 7.5% or 8%. Pushing too aggressively for a low number can cause frequent low blood sugar episodes, which carry their own risks.
How A1C Translates to Daily Blood Sugar
If you check your blood sugar at home, it helps to understand what your A1C actually looks like day to day. The conversion formula is: multiply your A1C by 28.7, then subtract 46.7. That gives you an estimated average glucose in mg/dL.
Here’s how common A1C levels translate:
- 6%: about 126 mg/dL average
- 6.5%: about 140 mg/dL
- 7%: about 154 mg/dL
- 8%: about 183 mg/dL
- 9%: about 212 mg/dL
- 10%: about 240 mg/dL
Keep in mind these are averages. An A1C of 7% could mean your blood sugar sat steadily around 154, or it could mean you swung between 80 and 250 throughout the day. The A1C alone can’t tell you which pattern you’re living with, which is why daily monitoring and continuous glucose monitors give a fuller picture.
Targets During Pregnancy
Pregnancy tightens the goal considerably. For women with pre-existing diabetes, the target during the first trimester is below 7% and as close to 6% as possible without causing low blood sugar. By the second and third trimesters, the goal drops to below 6%. These stricter targets reflect the fact that even moderately elevated blood sugar during pregnancy raises the risk of complications for both mother and baby.
Targets for Children and Older Adults
Children and adolescents with type 1 diabetes now have a recommended target of 6.5% or below when they use advanced technology like continuous glucose monitors and automated insulin pumps that help prevent dangerous lows. Without that technology, the target is 7% or below, the same as for most adults.
For older adults, especially those over 80 or living with multiple chronic conditions, the approach shifts. Rather than chasing a specific number, the priority becomes preventing symptoms of high blood sugar, like fatigue, blurry vision, and frequent infections. Aggressively lowering A1C in someone with limited life expectancy or significant frailty can cause more harm than benefit, largely because of the increased risk of severe low blood sugar episodes that can lead to falls, confusion, or hospitalization.
When Your A1C Might Be Inaccurate
The A1C test depends on normal red blood cell behavior, so anything that changes how long your red blood cells survive can skew the result. Iron-deficiency anemia, sickle cell disease, significant kidney disease, and liver failure can all produce A1C readings that are falsely high or falsely low.
Hemoglobin variants also matter. The most common ones are hemoglobin S (associated with sickle cell trait), hemoglobin C, hemoglobin D, and hemoglobin E. These variants can interfere with certain lab methods used to measure A1C, though not all methods are affected equally. If you carry one of these variants, your doctor may use a different type of A1C assay or rely on alternative tests like fructosamine, which measures blood sugar over a shorter two-to-three-week window.
Recent blood loss, blood transfusions, and pregnancy itself can also shift A1C results. If your A1C doesn’t match what your daily glucose readings are telling you, it’s worth asking whether one of these factors could be at play.
How Often to Get Tested
If you have diabetes and your blood sugar is stable and at your target, testing twice a year is typically sufficient. If you’ve recently changed medications, are working to bring your numbers down, or aren’t yet meeting your goals, testing every three months gives you a more timely read on whether your approach is working. For people without diabetes, an A1C test as part of routine bloodwork every few years is generally enough, though your doctor may test more often if you have risk factors like obesity, a family history of diabetes, or a previous prediabetes result.