A1C results fall into three main ranges: below 5.7% is normal, 5.7% to 6.4% indicates prediabetes, and 6.5% or higher means diabetes. These thresholds are the standard used for diagnosis, but the targets your doctor sets for managing diabetes can differ based on your age, health, and whether you’re pregnant.
The Three Diagnostic Ranges
The A1C test measures the percentage of your red blood cells’ hemoglobin that has glucose attached to it. Because red blood cells live roughly 90 to 120 days, the result reflects your average blood sugar over the past two to three months rather than a single moment in time.
- Normal: Below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher
A result in the prediabetes range means your blood sugar is elevated but not yet high enough for a diabetes diagnosis. This is the window where lifestyle changes, like losing a modest amount of weight and increasing physical activity, can sometimes prevent or delay progression to type 2 diabetes. A single A1C of 6.5% or above is typically confirmed with a repeat test before a formal diabetes diagnosis is made.
What Each A1C Translates to in Daily Blood Sugar
Your A1C percentage maps to an estimated average glucose (eAG), which is the number you’d see on a blood sugar meter averaged over months. The conversion formula is: (28.7 × A1C) − 46.7 = eAG in mg/dL. Here’s what that looks like in practice:
- A1C 5.0%: ~97 mg/dL
- A1C 6.0%: ~126 mg/dL
- A1C 6.5%: ~140 mg/dL
- A1C 7.0%: ~154 mg/dL
- A1C 8.0%: ~183 mg/dL
- A1C 9.0%: ~212 mg/dL
- A1C 10.0%: ~240 mg/dL
This is useful because many people check their blood sugar at home with a fingerstick and want to understand how those daily readings connect to the A1C number their doctor reports. An A1C of 7%, for example, means your blood sugar has averaged around 154 mg/dL, even if individual readings swing higher and lower throughout the day.
Management Targets for People With Diabetes
The diagnostic threshold of 6.5% is where diabetes begins, but the A1C goal you aim for after diagnosis depends on your situation. For most adults with type 2 diabetes, a target below 7% is standard. That corresponds to an average blood sugar of about 154 mg/dL.
For older adults, especially those over 65 with multiple chronic conditions or cognitive impairment, guidelines from the Endocrine Society recommend more lenient targets. Pushing A1C too low in this group increases the risk of hypoglycemia (dangerously low blood sugar), which can cause falls, confusion, and hospitalizations. The exact target varies, but avoiding hypoglycemia becomes the higher priority.
Children and Adolescents
For children and teens with type 1 diabetes, the International Society for Pediatric and Adolescent Diabetes (ISPAD) recommends an A1C of 6.5% or below when the child has access to advanced tools like continuous glucose monitors and automated insulin pumps, and can reach that target safely. In other situations, the recommended target is 7% or below. These are tighter than historical pediatric goals, reflecting improvements in diabetes technology that make lower levels achievable without as much risk of dangerous lows.
During Pregnancy
Pregnancy calls for stricter control. Most guidelines recommend an A1C below 6% during pregnancy to reduce the risk of complications for both the mother and baby. For women with pre-existing diabetes who are planning to conceive, a target of 6.5% or lower before becoming pregnant is recommended to give the pregnancy the safest possible start.
When Results Can Be Misleading
The A1C test assumes your red blood cells have a normal lifespan and normal hemoglobin. Several conditions break that assumption and can push your result artificially high or low.
Hemoglobin variants, such as sickle cell trait (HbS) or hemoglobin E trait (HbE), are among the most common sources of interference. Depending on the specific lab method used to run the test, these variants can produce falsely high or falsely low readings. With HbE trait, for example, results tend to be artificially lowered when the lab doesn’t detect the variant. The clinical concern is real: a falsely low A1C could mean your diabetes is undertreated because the numbers look better than they actually are.
Conditions that shorten red blood cell lifespan, such as hemolytic anemia or significant blood loss, also tend to lower A1C results. When red blood cells don’t live as long, they have less time to accumulate glucose on their hemoglobin, so the test underestimates your true average blood sugar. Conversely, iron deficiency anemia can push A1C readings higher because red blood cells circulate longer than usual. If you have any of these conditions, your doctor may use alternative tests like fructosamine or rely more heavily on direct blood sugar monitoring.
How Often to Get Tested
If your diabetes is well controlled and your A1C is at your target, testing every six months is the typical recommendation. If your treatment has recently changed, you’re not meeting your goals, or your A1C is above target, testing every three months gives you and your doctor a faster feedback loop to see whether adjustments are working. For people without diabetes who had a normal result, repeat testing every three years is common unless risk factors develop.
Percentage vs. mmol/mol
If you see A1C reported in mmol/mol rather than a percentage, you’re looking at the international (IFCC) unit system used in many countries outside the United States. The numbers look quite different: a normal A1C of 5.7% is about 39 mmol/mol, and the diabetes threshold of 6.5% equals 48 mmol/mol. A management target of 7% converts to 53 mmol/mol. Labs that use this system will display results accordingly, so it helps to know which scale you’re reading.