A good A1C for most adults is below 5.7%, which falls in the normal range. If you already have diabetes, the target shifts to below 7%. These numbers aren’t universal, though. Your ideal A1C depends on your age, health status, and whether you’re managing a specific condition.
A1C Ranges for Diagnosis
The A1C test measures your average blood sugar over the past two to three months. It works by detecting how much sugar has attached to hemoglobin, the protein in your red blood cells that carries oxygen. The higher your blood sugar has been running, the more sugar-coated hemoglobin you’ll have.
The diagnostic cutoffs are straightforward:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
A result in the prediabetes range means your blood sugar is elevated but hasn’t crossed into diabetes territory yet. This is the window where lifestyle changes, like losing 5 to 7% of your body weight and getting regular physical activity, can often prevent or delay progression. A diabetes diagnosis typically requires confirmation with a second test unless you already have clear symptoms like excessive thirst, frequent urination, or unexplained weight loss.
What Your A1C Means in Everyday Numbers
A1C percentages can feel abstract. It helps to translate them into estimated average glucose (eAG), the kind of number you’d see on a home blood sugar meter. The American Diabetes Association provides a conversion formula, and here’s what the key levels look like in practical terms:
- A1C of 6%: average blood sugar of about 126 mg/dL
- A1C of 6.5%: about 140 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
Each full percentage point on the A1C scale corresponds to roughly a 29 mg/dL increase in average blood sugar. So the difference between a 7% and an 8% is meaningful, even though it looks small on paper.
Targets for People With Diabetes
If you’ve been diagnosed with diabetes, the goal for most adults is an A1C below 7%. That 7% threshold is where the risk of long-term complications (damage to the eyes, kidneys, nerves, and heart) starts climbing more steeply. Keeping your A1C below that level significantly reduces those risks.
But “below 7%” isn’t the right goal for everyone. Your doctor may recommend a different target based on several factors: how long you’ve had diabetes, what medications you take, your risk of low blood sugar episodes, and other health conditions you’re managing. Some people aim for below 6.5% if they can get there safely without frequent blood sugar drops. Others do better with a higher ceiling.
Targets for Older Adults
For older adults in good health, the standard below-7% goal still applies. But for those dealing with multiple chronic illnesses, cognitive decline, or difficulty with daily activities, the American Diabetes Association recommends a less strict target of below 8%. The reasoning is practical: aggressive blood sugar lowering in this group raises the risk of dangerous low blood sugar episodes (hypoglycemia), which can cause falls, confusion, and hospitalization.
For older adults with very complex health, including conditions like end-stage kidney disease or moderate to severe cognitive impairment, guidelines recommend stepping away from A1C targets altogether. The priority shifts to simply avoiding blood sugar extremes in either direction, keeping the person comfortable and functional rather than chasing a number.
Targets During Pregnancy
Pregnancy raises the stakes for blood sugar control. For women with pre-existing diabetes who are planning to become pregnant, the ideal A1C is below 6.5% before conception. High blood sugar during the earliest weeks of pregnancy increases the risk of birth defects, preeclampsia, and preterm delivery.
Once pregnant, the goal tightens further to below 6% if that’s achievable without frequent low blood sugar episodes. If hypoglycemia becomes a problem, the target may be relaxed to below 7%. There’s a catch with A1C during pregnancy, though: red blood cells turn over faster than usual, which can make A1C readings appear artificially low. For that reason, daily blood sugar monitoring is considered more reliable than A1C alone during pregnancy.
Targets for Children and Teens
For most children and adolescents with type 1 diabetes, the recommended A1C target is also below 7%. This is the same as the adult goal, though achieving it in younger patients can be especially challenging because of growth hormones, unpredictable eating patterns, and the difficulty of managing insulin around school and sports schedules. As with adults, the target should be individualized and revisited over time.
How Often to Test
A1C reflects roughly the last 90 to 120 days of blood sugar levels, which is the typical lifespan of a red blood cell. That timeline dictates how often testing is useful. If you’ve just started a new treatment plan or changed your diet, repeating the test before three months won’t give you an accurate picture because your blood still contains older red blood cells that formed before the change.
For people whose blood sugar is well controlled and stable, testing every six months is often sufficient. If your levels are above target or you’ve recently adjusted your treatment, testing every three months makes more sense. More frequent than that rarely adds useful information.
When A1C Results Can Be Misleading
The A1C test is reliable for most people, but certain conditions can skew results in either direction. Severe anemia, kidney failure, and liver disease can all interfere with the reading. Blood disorders like sickle cell disease and thalassemia affect hemoglobin directly, which makes the test less accurate. Blood transfusions, significant blood loss, and certain medications (including some opioids and HIV drugs) can also throw off results.
Early and late pregnancy can affect accuracy as well, as mentioned above. If you have any of these conditions, your doctor may rely more heavily on other measures of blood sugar control, such as fructosamine testing or continuous glucose monitoring, rather than A1C alone. The important thing to know is that a single A1C number doesn’t always tell the full story, especially if your health situation is complicated.