A good hemoglobin A1c is below 5.7%, which falls in the normal range and indicates healthy blood sugar control over the past two to three months. If you already have diabetes, the target shifts: most adults aim for an A1c under 7%, though your ideal number depends on your age, health, and risk of low blood sugar episodes.
What A1c Ranges Mean
The A1c test measures the percentage of your red blood cells’ hemoglobin that has glucose attached to it. Because red blood cells live about three months, the test captures a rolling average of your blood sugar rather than a single snapshot. The CDC uses three ranges for diagnosis:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
A result in the prediabetes range doesn’t mean you’ll inevitably develop diabetes, but it does signal that your body is struggling to manage blood sugar efficiently. Lifestyle changes at this stage, particularly weight loss and regular physical activity, can bring an A1c back below 5.7%.
A1c Targets If You Have Diabetes
Once someone has diabetes, “good” no longer means the same as “normal.” The American Diabetes Association recommends an A1c below 7% for most non-pregnant adults, which corresponds to an estimated average blood sugar of about 154 mg/dL. Hitting that target significantly reduces the risk of complications affecting the eyes, kidneys, and nerves.
A lower target, such as under 6.5%, can be beneficial if you can reach it without frequent episodes of dangerously low blood sugar. On the other hand, a less strict goal of under 8% may make more sense for people who are older, have other serious health conditions, or experience harm from aggressive treatment. The right number is a conversation between you and your care team, balancing the benefits of tight control against the real risks of pushing too low.
What Your A1c Translates to in Daily Numbers
One reason doctors like the A1c test is that it converts neatly into an estimated average glucose, giving you a number you can compare to your meter or continuous glucose monitor readings. The formula is straightforward: multiply your A1c by 28.7, then subtract 46.7. Here are common conversions:
- 6% A1c: ~126 mg/dL average
- 6.5%: ~140 mg/dL
- 7%: ~154 mg/dL
- 8%: ~183 mg/dL
- 9%: ~212 mg/dL
- 10%: ~240 mg/dL
Keep in mind that this is an average. Two people with the same A1c can have very different daily patterns. One might have steady blood sugar throughout the day while the other swings between highs and lows that happen to average out to the same number. That’s why many clinicians now also look at time in range from continuous monitors, aiming for blood sugar to stay between 70 and 180 mg/dL at least 70% of the time.
Targets During Pregnancy
Pregnancy calls for tighter control. Guidelines from the UK’s National Institute for Health and Care Excellence recommend an A1c below 6.5% before conception for women with preexisting diabetes. An A1c above 10% carries enough risk to serious complications that medical teams strongly advise waiting to conceive until that number comes down. During pregnancy itself, blood sugar targets are typically managed through frequent daily glucose checks rather than relying on A1c alone, since the test’s three-month lag makes it too slow for the rapid adjustments pregnancy demands.
How Often to Get Tested
If your A1c is at your goal, testing every six months is the standard recommendation. If you’ve recently changed medications or your last result was above target, every three months gives a faster feedback loop. For people without diabetes who had a normal result, your doctor will likely recheck during routine physicals or if risk factors change.
When A1c Results Can Be Misleading
The test is reliable for most people, but certain conditions can skew results in either direction. Anything that shortens the lifespan of red blood cells, like hemolytic anemia or recent significant blood loss, will make your A1c appear falsely low because the cells haven’t been around long enough to accumulate glucose. Iron deficiency anemia pushes results in the opposite direction, producing a falsely high reading.
Genetic hemoglobin variants, which are more common in people of African, Mediterranean, and Southeast Asian descent, can also interfere with certain testing methods. Sickle cell trait and hemoglobin C trait are two well-known examples. Kidney disease adds another layer of complexity, since chemical changes to hemoglobin in renal failure and the effects of anemia treatment can both distort results. If any of these apply to you, your provider may use an alternative measure of blood sugar control, such as a fructosamine test, which reflects a shorter window of about two to three weeks.
Targets for Children and Adolescents
Children and teens with type 1 diabetes generally follow the same under-7% target as adults, but adjustments are common. Kids who can’t recognize or communicate symptoms of low blood sugar, or who don’t have access to advanced insulin delivery technology, may do better with a target under 7.5%. For young people with type 2 diabetes, the goal is often a bit stricter at under 6.5%, since their risk of low blood sugar is typically lower when managed with lifestyle changes and oral medications rather than insulin.