For most adults without diabetes, an ideal A1c is below 5.7%. If you have diabetes, the general target is below 7%, which translates to an estimated average blood sugar of about 154 mg/dL. But “ideal” isn’t one number for everyone. Your age, health status, risk of low blood sugar episodes, and even pregnancy can shift the goal up or down.
What A1c Measures
A1c (also called hemoglobin A1c or HbA1c) reflects your average blood sugar over roughly the past two to three months. It works by measuring how much glucose has attached to hemoglobin, the protein in red blood cells that carries oxygen. Because red blood cells live about 120 days, the test captures a rolling average rather than a single snapshot. The result is expressed as a percentage: the higher the number, the more sugar has been coating your red blood cells.
Each percentage point corresponds to a meaningful jump in average blood sugar. An A1c of 6% equals roughly 126 mg/dL, 7% equals about 154 mg/dL, and 8% equals approximately 183 mg/dL. These conversions help bridge the gap between your A1c result and the glucose numbers you might see on a home meter.
The Standard Ranges
The CDC uses three categories for A1c results:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
If your result falls in the prediabetes range, it means your blood sugar has been running higher than normal but not 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 make the biggest difference in preventing progression.
The Target for Most Adults With Diabetes
The American Diabetes Association recommends an A1c below 7% for most nonpregnant adults with diabetes, provided they can reach it without frequent or severe episodes of low blood sugar. That target is backed by decades of research showing it substantially lowers the risk of complications affecting the eyes, kidneys, and nerves. One large UK study found that an increase of roughly one percentage point in A1c was associated with a 37% increased risk of retinopathy or kidney disease.
Some people can safely aim even lower. If you can maintain an A1c below 6.5% without dangerous blood sugar drops or an exhausting treatment routine, that tighter goal may offer additional protection. This is more realistic for people early in their diagnosis, those using newer medications that carry a low risk of hypoglycemia, or those with access to continuous glucose monitors.
When a Higher Target Makes More Sense
A lower A1c is not always better. The landmark ACCORD trial found that pushing aggressively toward an A1c of 6.5% or below in people with longstanding type 2 diabetes actually increased the risk of severe hypoglycemia and premature death compared to a more relaxed target of around 7.5% to 8.5%. The benefits of tight control can be outweighed by the dangers of frequent low blood sugar, especially when insulin or certain older medications are involved.
A target of up to 8% may be more appropriate if you have a limited life expectancy, deal with severe or frequent low blood sugar episodes, or live with conditions where the burden of intensive treatment outweighs the long-term payoff. The key principle is that the goal should reflect your whole health picture, not just your blood sugar.
Targets for Older Adults
Age alone doesn’t determine your A1c goal, but overall health status does. The ADA breaks older adults into three broad categories, each with different targets:
- Healthy older adults with few chronic conditions and sharp cognitive function: A1c below 7.0% to 7.5%
- Complex health with multiple chronic illnesses or mild to moderate cognitive decline: A1c below 8.0%
- Very complex or poor health with significant functional limitations or end-stage illness: No fixed A1c target. The focus shifts entirely to preventing dangerously high or low blood sugar rather than chasing a number.
For older adults taking insulin or sulfonylureas, an A1c below 7% is now widely considered overtreatment. The risk of a severe hypoglycemic episode, which can cause falls, confusion, hospitalization, or worse, rises sharply with tighter control in this group.
Targets During Pregnancy
If you have pre-existing diabetes and are planning to become pregnant, the recommended A1c is below 6.5% before conception. Blood sugar control during the earliest weeks of pregnancy, often before you know you’re pregnant, is critical for reducing the risk of birth defects and complications. Pregnancy itself can make A1c readings less reliable because red blood cells turn over faster, typically shortening their lifespan from about 120 days to around 90. A1c values tend to drop between weeks 12 and 24 of gestation and may rise again in the third trimester, so your care team will likely rely more heavily on daily glucose monitoring during this time.
Targets for Children and Teens
For most children and adolescents with type 1 diabetes, the recommended A1c is below 7%, the same as for adults. A slightly higher target of below 7.5% is considered more suitable for younger children who can’t recognize or communicate symptoms of low blood sugar, or for families without access to insulin pumps and continuous glucose monitors. Kids with a history of severe hypoglycemia or significant other health conditions may have a target below 8%. On the other end, some children on advanced technology during the early “honeymoon phase” of type 1 diabetes can safely aim below 6.5%.
When A1c Results Can Be Misleading
A1c is a reliable test for most people, but certain conditions can push the number artificially higher or lower than your true average blood sugar.
Your A1c may read falsely high if you have iron deficiency anemia, vitamin B12 or folate deficiency, or have had your spleen removed. All of these cause red blood cells to live longer than usual, giving sugar more time to accumulate on hemoglobin. Severe kidney disease with high urea levels and very high triglycerides can also inflate the result.
Your A1c may read falsely low if you have conditions that destroy red blood cells faster than normal, including hemolytic anemia, significant blood loss, an enlarged spleen, or end-stage kidney disease with chronic anemia. Pregnancy also lowers A1c readings for the reasons described above. Recent blood transfusions can skew results in either direction depending on the donor’s blood sugar levels.
If you have any of these conditions, your doctor may use alternative measures like fructosamine (which reflects a two- to three-week average) or rely more on daily glucose readings to get an accurate picture.
How Often to Get Tested
If your diabetes is well controlled and your treatment hasn’t changed, testing every six months is sufficient. If you’re adjusting medications, recently diagnosed, or not meeting your target, testing every three months gives faster feedback. Clinical guidelines recommend against testing more than four times per year, since the test reflects a two- to three-month window and more frequent checks won’t add useful information.
For people without diabetes who had a normal result, repeating the test every three years is a common screening interval, though your doctor may test sooner if you have risk factors like obesity, a family history of diabetes, or a previous prediabetes result.