A good A1C number is below 5.7%, which falls in the normal range and means your average blood sugar over the past two to three months has been healthy. If you already have diabetes, the general target shifts to below 7%, though your specific goal depends on your age, overall health, and other factors.
What Your A1C Number Means
The A1C test measures the percentage of your red blood cells that have sugar attached to them. Because red blood cells live for about three months, the test gives a snapshot of your average blood sugar over roughly 8 to 12 weeks, rather than a single moment in time. The CDC uses these ranges to categorize results:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher
If you don’t have diabetes and your result comes back below 5.7%, your blood sugar regulation is working well. A result between 5.7% and 6.4% means your blood sugar is higher than it should be, but not yet in the diabetes range. This is a window where lifestyle changes, like adjusting your diet and increasing physical activity, can often prevent or delay progression to type 2 diabetes.
A1C Targets If You Have Diabetes
For most adults with diabetes, keeping A1C below 7% is the standard goal. That number corresponds to an estimated average blood sugar of about 154 mg/dL. Each percentage point on the A1C scale translates to a meaningful change in daily blood sugar levels:
- A1C of 6%: average blood sugar of about 126 mg/dL
- A1C of 7%: about 154 mg/dL
- A1C of 8%: about 183 mg/dL
- A1C of 9%: about 212 mg/dL
- A1C of 10%: about 240 mg/dL
The difference between each percentage point matters more than it might seem. For every 1% drop in A1C, the risk of complications affecting the eyes, kidneys, and nerves drops by 33% to 37%. Bringing an A1C from 9% down to 7%, for example, roughly cuts those risks in half.
When Targets Are Higher or Lower
Not everyone with diabetes should aim for the same number. Older adults with significant health conditions or a limited life expectancy often have a target of 8% or below, because pushing blood sugar too low increases the risk of dangerous drops (hypoglycemia). For older adults in poor overall health, targets may be set as high as 8.5%, which corresponds to an average blood sugar of about 200 mg/dL. The priority in these cases shifts from tight blood sugar control to avoiding both severe highs and lows that affect quality of life.
On the other end of the spectrum, people planning a pregnancy are advised to get their A1C below 6.5% before conceiving. An A1C above 10% poses serious enough risks to both mother and baby that medical guidance is to delay pregnancy until it comes down.
Younger adults who are otherwise healthy and recently diagnosed may be encouraged to aim closer to 6.5%, especially if they can reach that goal without frequent low blood sugar episodes. The key factor is always the balance between lower blood sugar and the risk of hypoglycemia.
How Often to Get Tested
The American Diabetes Association recommends testing every six months if your A1C is within your target range. If your medications have recently changed, or your last result was above your goal, testing every three months gives you and your care team faster feedback on whether adjustments are working.
For people without diabetes who had a normal result, retesting every three years is typical unless risk factors like weight, family history, or age suggest more frequent screening.
A1C vs. Daily Blood Sugar Monitoring
A1C gives you the big picture, but it has blind spots. Two people can have the same A1C of 7% while experiencing very different daily patterns. One might have steady blood sugar throughout the day, while the other swings between highs and lows that average out to the same number. The A1C test can’t distinguish between these two scenarios.
This is where continuous glucose monitors (CGMs) add a layer of detail. CGMs track blood sugar every few minutes, producing a metric called “time in range,” which shows the percentage of your day spent within a healthy blood sugar window. More clinicians are using time in range alongside A1C to get a fuller picture. If you use a CGM, your time in range data can reveal patterns that a single A1C number would miss, like overnight spikes or post-meal crashes.
What Can Throw Off Your Results
Certain health conditions can make your A1C read higher or lower than your actual blood sugar levels would suggest. Any condition that affects red blood cells, including iron deficiency anemia, sickle cell trait, or kidney disease, can distort the result. Recent blood loss or blood transfusions can also skew the number. If you have any of these conditions, your doctor may rely more heavily on direct blood sugar measurements or alternative tests to assess your glucose control.
Pregnancy itself can also affect A1C accuracy, since red blood cell turnover speeds up during the second and third trimesters. This is another reason daily glucose monitoring takes on a bigger role during pregnancy.