A1C levels explained: what your number means and what to do if it's above target

What do A1C levels mean?

Your A1C level, also called HbA1c or hemoglobin A1C, reflects your average blood sugar over about the past 3 months.^[1] Sugar in the blood attaches to hemoglobin, a protein in red blood cells, and the test reports the percentage of red blood cells with sugar-coated hemoglobin.^[1] Red blood cells are replaced roughly every 3 months, which is why the result looks back over that period.^[1]

A1C is one of several ways your care team looks at blood sugar. Checks with a meter or a continuous glucose monitor (CGM) show what is happening now, and A1C shows the longer pattern.^[1] This guide explains A1C ranges, how goals are set, what can affect the result and what to ask if yours is above target. It cannot tell you what your own number means for your treatment.

What is the normal A1C range, and what range means diabetes?

An A1C below 5.7% is in the normal range, 5.7% to 6.4% is in the prediabetes range, and 6.5% or above is in the diabetes range.^[1] These ranges are used for diagnosis. Once you live with diabetes, your result is compared with the goal you and your care team have set.^[1][2]

You do not need to fast before an A1C test. Other tests taken at the same visit, such as cholesterol, may need fasting.^[1]

How does an A1C level translate into average blood sugar?

Each A1C level corresponds to an estimated average glucose, or eAG, measured in mg/dL.^[2]

These values come from a single study of 507 adults published in 2008, and ADA notes it is unclear how closely they match averages from modern CGMs.^[2] An A1C also does not show highs, lows or how much readings swing during a day.^[2] For people whose readings vary a lot, ADA describes reading A1C together with meter or CGM results.^[2]

What A1C target do most people with diabetes have?

For many nonpregnant adults, ADA's 2026 Standards of Care set an A1C goal below 7.0%, as long as it can be reached without severe lows or lows that affect health or quality of life.^[2] CDC's guide to the A1C test describes the goal for most people as 7.0% or less.^[1]

Goals are set individually. ADA describes lower goals, such as below 6.5%, for some people in good health with a low risk of lows. It describes less strict goals, sometimes up to 8.0%, for people with complex health needs or where the harms of treatment may outweigh the benefits.^[2] The factors include how long you have had diabetes, your age, other conditions, your risk of lows, and your own preferences and resources.^[2] Pregnancy, children and teens have separate guidance.^[2]

If you use a CGM, ADA also sets a goal for time in range: more than 70.0% of readings between 70 and 180 mg/dL for many adults.^[2] Two retrospective studies cited by ADA link that goal to an A1C of about 7.0%.^[2]

ADA's standards note that agreeing a specific goal during appointments has been shown to improve blood sugar outcomes.^[2] If you are not sure what your goal is, that is a reasonable first question.

What can make an A1C result inaccurate?

Conditions that affect red blood cells or hemoglobin can make an A1C read falsely high or low.^[1] CDC lists severe anemia, kidney failure, liver problems, blood conditions such as sickle cell anemia or thalassemia, some medicines including opioids and some HIV medicines, blood loss or transfusions, and early or late pregnancy.^[1]

ADA adds that A1C cannot be measured in some inherited hemoglobin variants. In those cases, a fructosamine test or a CGM can be used instead.^[2] Point-of-care A1C tests done during an appointment may be less accurate than laboratory tests.^[2] ADA also notes that A1C and meter or CGM results can disagree because of large swings in readings, device inaccuracy, or factors that affect the A1C itself.^[2]

If your A1C does not match what your readings show, or one of these factors applies to you, tell your care team. You might say: "My meter readings look lower than this A1C suggests. Could something be affecting the test?" This is an illustrative prompt, not a quote from a real patient. Use your own words and choose how much you want to share.

What can I do if my A1C is higher than my target?

Ask how far above your goal you are and what your readings show, then look together at what has changed. An A1C reflects the past few months, but it does not explain why the number moved.^[2]

1. Ask what your goal is and how your result compares with it.
2. Bring your meter readings or CGM report, since A1C alone does not show patterns, highs or lows.^[2]
3. List anything that changed in the past 3 months, such as an illness, a new medicine, a different work schedule, side effects or the cost of supplies.
4. Ask whether the plan needs to change now or after more readings.
5. Agree when you will be tested again.

CDC notes that higher A1C levels are linked to health complications, and that reaching and keeping your goal is part of living well with diabetes.^[1]

If your readings are high right now and you feel unwell, read what to do when blood sugar runs high. If your A1C stays above target while you take medication, read questions to ask when blood sugar stays high on medication.

How often is A1C checked with diabetes?

ADA recommends checking at least twice a year, and more often, such as every 3 months, if you are not meeting your goal, have recently changed treatment, have frequent highs or lows, or your health has changed.^[2] People who reach their goal and stay there may only need the test twice a year.^[2] Ask your care team which schedule fits you. The American Diabetes Association's Understanding A1C page has more background on the test.

Where can I find support with A1C questions?

The right support depends on whether you need help understanding a result, practical help with daily care, or time with a professional. Compare diabetes resources to see what each service offers and where it is available. Explore diabetes patient questions for illustrative ways to put a question into words. To find diabetes education near you, search ADA's directory of diabetes education programs. The mama health app is one place to ask about your condition and get answers grounded in medical science and the experience of others living with diabetes. Learn more about its diabetes support.