For most adults without diabetes, A1C should be below 5.7%. If you have diabetes, the general target is below 7%, though your ideal number depends on your age, overall health, and how long you’ve had diabetes. These thresholds guide diagnosis and management, but the numbers mean different things depending on where you are in that spectrum.
What A1C Actually Measures
A1C reflects your average blood sugar over roughly the past three months. Glucose in your bloodstream attaches to hemoglobin, the protein inside red blood cells that carries oxygen. The more glucose in your blood, the more hemoglobin gets coated. Since red blood cells live about 90 days, measuring how much glucose is stuck to them gives a reliable picture of your blood sugar control over that entire window, not just a single moment.
This makes A1C different from a finger-stick glucose reading, which only captures what’s happening right now. You could have a normal fasting glucose on a given morning but still have an elevated A1C if your blood sugar has been running high after meals or overnight for weeks.
The Diagnostic Ranges
Three categories define where your A1C falls:
- 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 higher than normal but not yet at the diabetes threshold. About 80 million Americans fall into this category. The practical significance: prediabetes is the stage where lifestyle changes (losing 5 to 7% of body weight, regular physical activity) are most effective at preventing or delaying progression to type 2 diabetes.
What A1C Translates to in Daily Blood Sugar
A1C percentages can feel abstract. Converting them to estimated average glucose gives a more intuitive sense of what’s happening in your body day to day. Here are the common conversions:
- A1C of 5%: average blood sugar around 97 mg/dL
- A1C of 6%: average blood sugar around 126 mg/dL
- A1C of 7%: average blood sugar around 154 mg/dL
- A1C of 8%: average blood sugar around 183 mg/dL
- A1C of 9%: average blood sugar around 212 mg/dL
- A1C of 10%: average blood sugar around 240 mg/dL
Each 1% increase in A1C corresponds to roughly a 29 mg/dL rise in average glucose. So the difference between hitting a 7% target versus running at 8% is an average daily blood sugar of about 154 versus 183, a gap that compounds over months and years in terms of damage to blood vessels, nerves, and organs.
Targets for Adults With Diabetes
The American Diabetes Association recommends an A1C below 7% for most non-pregnant adults with diabetes. This target balances long-term protection against complications (eye disease, kidney damage, nerve problems) with the practical risk of pushing blood sugar too low.
Going lower than 7% is reasonable and sometimes beneficial if you can get there safely, meaning without frequent episodes of low blood sugar. Some people with newly diagnosed type 2 diabetes, a strong motivation to manage their condition, and no history of dangerous blood sugar drops aim for below 6.5%.
A more relaxed target of below 8% may be appropriate if you have a long history of diabetes, serious complications already in place, limited life expectancy, or a pattern of severe low blood sugar episodes. The logic here is straightforward: aggressively lowering blood sugar carries its own risks, and those risks become harder to justify when the potential long-term benefits shrink. Frequent or severe low blood sugar is itself dangerous, and avoiding it sometimes matters more than hitting a tighter number.
Targets for Older Adults
A1C goals shift with age and health status, and the 2024 ADA Standards of Care breaks older adults into three groups:
Healthy older adults with few chronic conditions and good cognitive function should aim for an A1C below 7.0 to 7.5%. This is close to the general adult target, reflecting the fact that a healthy 68-year-old still benefits from strong glucose control over the coming decades.
Older adults with multiple chronic illnesses (three or more serious conditions like heart failure, kidney disease, or depression) or mild cognitive impairment have a recommended target below 8.0%. For this group, the treatment burden itself, including the complexity of managing medications and the risk of hypoglycemia, becomes a bigger factor in the equation.
For those in very poor health, with end-stage chronic illness or significant cognitive or functional impairment, the focus shifts away from hitting a specific A1C number entirely. The priority becomes avoiding dangerously low or symptomatically high blood sugar rather than optimizing a lab value.
Targets for Children and Teens
For most children with type 1 diabetes, the recommended A1C is below 7%, the same as for adults, with an emphasis on personalizing the goal. A slightly higher target of below 7.5% may be more appropriate for younger children who can’t recognize or communicate symptoms of low blood sugar, or for families without access to newer insulin formulations and glucose monitoring technology. During the “honeymoon period” shortly after diagnosis, when the pancreas still produces some insulin, A1C below 6.5% may be achievable without excessive risk.
When A1C Results Can Be Misleading
A1C is reliable for most people, but certain conditions can skew results in either direction. Knowing about these is especially important if your A1C doesn’t match what your daily glucose readings suggest.
Iron deficiency anemia is one of the most common causes of falsely high A1C. Vitamin B12 and folate deficiency anemias have the same effect. The mechanism: when red blood cells turn over more slowly (as they do in these anemias), hemoglobin spends more time exposed to glucose in the bloodstream, picking up more of it and inflating the result. Chronic alcohol use, chronic use of aspirin-type medications, and severe kidney disease can also push A1C readings artificially upward.
On the other side, conditions that speed up red blood cell turnover tend to lower A1C falsely. Pregnancy, recent blood loss, an enlarged spleen, and certain medications can all produce a reading that looks better than reality. Recent blood transfusions can push results in either direction depending on the circumstances.
Hemoglobin variants, most commonly hemoglobin S (sickle cell trait) and hemoglobin C, add another layer of complexity. These genetic variations in hemoglobin structure can cause the test to read either high or low depending on the specific lab method used. People who carry one copy of these variants (heterozygous) generally get reliable results, but those with two copies (homozygous) may need alternative testing methods like fructosamine to assess blood sugar control accurately.
How Often to Get Tested
If you have diabetes and your blood sugar is stable and at goal, testing twice a year is sufficient. If your treatment has recently changed or you’re not meeting your target, testing every three months gives you and your provider enough data to adjust course. For people without diabetes, A1C is typically checked as part of routine screening, with frequency depending on your risk factors for developing diabetes.
Because A1C reflects a 90-day average, testing more frequently than every three months rarely adds useful information. The result won’t fully reflect changes you made less than two to three months ago.