A good A1C number for someone without diabetes is below 5.7%. If you have diabetes, the general target is below 7%, though your ideal number depends on your age, health status, and treatment plan. The A1C test measures the percentage of your red blood cells coated with glucose, giving a snapshot of your average blood sugar over the past two to three months.
How the A1C Test Works
Glucose in your bloodstream naturally attaches to hemoglobin, the protein inside red blood cells that carries oxygen. The more glucose circulating in your blood, the more hemoglobin gets coated. Since red blood cells live about three months, measuring the percentage of glucose-coated hemoglobin reveals your average blood sugar for that entire window. That’s what makes A1C more useful than a single finger-stick reading: it captures the big picture rather than a single moment.
The Three A1C Categories
The National Institute of Diabetes and Digestive and Kidney Diseases defines three ranges:
- 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. This is the window where lifestyle changes, like losing 5 to 7% of body weight and getting regular physical activity, can often prevent or delay progression to type 2 diabetes. If your A1C comes back at 6.5% or higher on two separate tests, that typically confirms a diabetes diagnosis.
What A1C Translates to in Daily Blood Sugar
A1C percentages can feel abstract. Translating them into estimated average glucose (eAG) in mg/dL makes the number more concrete. Here’s what common A1C values look like in terms of the blood sugar levels you’d see on a glucose meter:
- 6.0%: ~126 mg/dL average
- 6.5%: ~140 mg/dL
- 7.0%: ~154 mg/dL
- 7.5%: ~169 mg/dL
- 8.0%: ~183 mg/dL
- 9.0%: ~212 mg/dL
So the difference between a 7% A1C and an 8% A1C is roughly 29 mg/dL in average daily blood sugar. That gap matters over time because consistently higher glucose levels accelerate damage to blood vessels, nerves, kidneys, and eyes.
The Standard Target for Adults With Diabetes
The American Diabetes Association’s 2024 Standards of Care recommends an A1C below 7% for most nonpregnant adults with diabetes. Alongside that A1C goal, the guidelines suggest keeping fasting blood sugar between 80 and 130 mg/dL and post-meal spikes below 180 mg/dL (measured one to two hours after eating).
That said, the ADA emphasizes there’s no one-size-fits-all number. Your target could be tighter or more relaxed depending on several factors: how long you’ve had diabetes, your age, whether you have heart disease or other complications, and how prone you are to dangerously low blood sugar episodes (hypoglycemia). Someone recently diagnosed and otherwise healthy might aim for closer to 6.5%, while someone with a long history of diabetes and frequent low blood sugar episodes might be better served by a slightly higher target.
Targets for Older Adults
For older adults, avoiding low blood sugar becomes just as important as controlling high blood sugar. Hypoglycemia can cause falls, confusion, and heart rhythm problems, risks that increase with age and frailty. Canadian diabetes guidelines lay out adjusted targets based on functional status:
- Functionally dependent older adults: below 8.0%, or 7.1 to 8.5% if taking medications that carry a higher risk of low blood sugar (like insulin)
- Frail older adults or those with dementia: below 8.5%, or 7.1 to 8.5% on higher-risk medications
- End of life: A1C testing is no longer recommended. The focus shifts to avoiding symptoms from extremely high or low blood sugar
These higher targets reflect a practical trade-off. Aggressive glucose lowering in someone who is frail or cognitively impaired creates more immediate danger from hypoglycemia than the long-term complications it’s trying to prevent.
A1C Goals During Pregnancy
Pregnancy calls for tighter control because elevated blood sugar affects fetal development. The Joslin Diabetes Center recommends an A1C below 7% in the first trimester, ideally as close to 6% as possible without causing low blood sugar. By the second and third trimesters, the goal drops to below 6%. Women planning a pregnancy are advised to reach an A1C under 7% before conceiving to reduce the risk of complications in the earliest weeks of development.
When A1C Results Can Be Misleading
The test relies on red blood cells behaving normally, so anything that changes those cells can skew results. Iron deficiency anemia, which is extremely common worldwide, tends to push A1C readings falsely high. Conditions that shorten the lifespan of red blood cells, like hemolytic anemia or significant blood loss, do the opposite: red blood cells don’t survive long enough to accumulate glucose, so A1C reads falsely low.
Genetic hemoglobin variants, including sickle cell trait and hemoglobin C trait, can also interfere with results depending on the laboratory method used. Kidney failure creates another wrinkle. Chemical changes to hemoglobin in people on dialysis can make A1C unreliable, and alternative markers like glycated albumin sometimes give a more accurate picture in those cases.
If you have any of these conditions, your A1C number alone may not reflect your actual blood sugar control. A combination of A1C with home glucose monitoring or continuous glucose monitoring typically gives a fuller picture.
How Often to Get Tested
If you don’t have diabetes and your previous results were normal, testing every three years is standard. For people with prediabetes, annual testing helps track whether blood sugar is trending upward. If you have diabetes and your blood sugar is well controlled on a stable treatment plan, testing twice a year is generally sufficient. When your treatment changes or you’re not yet at your target, testing every three months gives you and your provider timely feedback on whether adjustments are working.
Because the test reflects a two-to-three-month average, checking more frequently than every three months won’t yield meaningful new information. The result you get today is already looking backward at blood sugar levels from weeks ago.