A normal A1C is below 5.7%. This number reflects your average blood sugar over the past two to three months, giving a more complete picture than a single finger-stick reading. If you already have diabetes, the target shifts higher, and the “right” number depends on your age, overall health, and risk of blood sugar dropping too low.
The Three Diagnostic Ranges
A1C results fall into three categories:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
A result of 5.7% doesn’t mean you’ve crossed a cliff into danger. It means your blood sugar has been running higher than ideal, and the trend matters more than any single test. Prediabetes is a window where lifestyle changes can genuinely reverse course. A result of 6.5% or above on two separate tests is typically enough for a diabetes diagnosis.
What Each Percentage Means in Daily Blood Sugar
A1C percentages can feel abstract. Each point corresponds to a real average blood sugar level you’d see on a glucose meter. The American Diabetes Association uses a formula (28.7 × A1C − 46.7) to estimate that average, and the numbers are more intuitive than the percentages:
- A1C of 6%: average blood sugar around 126 mg/dL
- A1C of 6.5%: around 140 mg/dL
- A1C of 7%: around 154 mg/dL
- A1C of 8%: around 183 mg/dL
- A1C of 9%: around 212 mg/dL
- A1C of 10%: around 240 mg/dL
These are averages, so they smooth out the highs and lows. Someone with an A1C of 7% isn’t sitting at 154 mg/dL all day. Their blood sugar might swing from 90 after fasting to 200 after a meal. The A1C captures the overall trend.
Targets If You Have Diabetes
Once you have a diabetes diagnosis, the goal isn’t necessarily to get your A1C back below 5.7%. Pushing blood sugar too low carries its own serious risks, including dangerous episodes of hypoglycemia. Instead, guidelines set targets that balance long-term protection against short-term safety.
The two major professional organizations in the U.S. set slightly different targets. The American Diabetes Association recommends an A1C below 7% for most nonpregnant adults. The American Association of Clinical Endocrinologists sets a tighter goal of 6.5% or below, but only for people without serious coexisting illnesses and at low risk of hypoglycemia. For people who have experienced severe low blood sugar episodes, have advanced kidney disease, or have had diabetes for many years with difficulty reaching goals, the AACE relaxes the target to 7% to 8%.
In practice, your doctor will pick a target somewhere in this range based on your personal situation. Someone who is 40, otherwise healthy, and recently diagnosed will likely aim for under 7%. Someone managing multiple chronic conditions may aim for under 8%, and that’s perfectly appropriate.
Targets for Older Adults
A1C goals loosen with age, particularly after 70. The reason is straightforward: aggressive blood sugar lowering in older adults increases the risk of dangerous lows, which can cause falls, confusion, and hospitalization. The long-term benefits of tight control also shrink when life expectancy is shorter.
The ADA framework breaks it down by overall health status rather than age alone. Older adults who are otherwise healthy and mentally sharp aim for an A1C below 7.5%. Those managing several chronic conditions, or who have mild to moderate cognitive decline, aim for below 8%. For people in long-term care or with end-stage illness, the target loosens further to below 8.5%, with the priority shifting toward preventing symptoms of high blood sugar rather than hitting a specific number.
The International Diabetes Federation draws similar lines: 7% to 7.5% for independent older adults, and 7% to 8% for those who are frail or have dementia. The American College of Physicians goes a step further, stating that for people over 80, living in nursing homes, or dealing with conditions like advanced cancer or severe heart failure, targeting a specific A1C number can cause more harm than good.
Targets for Children and Teens
The American Diabetes Association recommends an A1C of 7% or lower for all children and adolescents with diabetes. This is the same as the general adult target, reflecting the importance of good blood sugar control during the years when complications from diabetes can accumulate over decades. Reaching this goal in kids, especially with type 1 diabetes, often requires close monitoring and frequent insulin adjustments.
When the Test Can Be Wrong
A1C measures how much sugar has attached to your red blood cells over their lifespan, which is roughly 90 to 120 days. Anything that changes how long your red blood cells live, or how many you have, can throw off the result.
Iron-deficiency anemia, sickle cell trait, and other blood disorders can make A1C readings inaccurately high or low. Kidney failure and liver disease can also skew results. If you have one of these conditions, your doctor may rely on other blood sugar tests instead, such as a fructosamine test or direct glucose measurements, to get an accurate picture.
How Often to Get Tested
Because A1C reflects a two- to three-month window, testing more often than every three months doesn’t give useful new information. The red blood cells carrying the old measurement haven’t fully turned over yet, so the result will still reflect the previous period.
If your blood sugar is well controlled and your treatment plan hasn’t changed, testing every six months is sufficient. After a medication change, a new diet, or a shift in exercise habits, retesting at the three-month mark makes sense, since that’s when the full effect of the change will show up in your results. Testing earlier than three months rarely tells you anything actionable.