A good A1C number is below 5.7%, which is considered normal and means your average blood sugar over the past two to three months has been in a healthy range. Once your A1C reaches 5.7%, you’re in prediabetes territory, and 6.5% or higher indicates diabetes. But “good” doesn’t always mean the same number for everyone. Your ideal target depends on your age, health status, and whether you’re already managing diabetes.
The Three A1C Ranges
The CDC uses these cutoffs to classify A1C results:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
If you don’t have diabetes and your A1C comes back below 5.7%, your blood sugar regulation is working well. A result in the prediabetes range is a signal that your body is starting to have trouble processing sugar efficiently, but it’s also the stage where lifestyle changes can make the biggest difference in preventing progression to diabetes.
What A1C Actually Measures
Your A1C reflects how much sugar has attached to your red blood cells over their roughly three-month lifespan. Unlike a fasting glucose test, which captures a single moment, A1C gives a broader picture of your blood sugar patterns. That’s why it’s the preferred test for diagnosing diabetes and tracking how well treatment is working over time.
Each A1C percentage corresponds to an estimated average glucose level. Here’s how they translate:
- A1C 6%: average blood sugar of about 126 mg/dL
- A1C 6.5%: about 140 mg/dL
- A1C 7%: about 154 mg/dL
- A1C 8%: about 183 mg/dL
- A1C 9%: about 212 mg/dL
- A1C 10%: about 240 mg/dL
These conversions can help you connect your A1C to the daily glucose numbers you might see on a home meter or continuous glucose monitor.
Targets If You Have Diabetes
If you’ve been diagnosed with diabetes, the goal shifts from “normal” to a target that reduces complications while keeping you safe from dangerously low blood sugar. For most adults with type 2 diabetes, the general target is an A1C below 7%. That corresponds to an average blood sugar of about 154 mg/dL.
For children and adolescents with type 1 diabetes, the American Diabetes Association also recommends a target below 7% for many patients, though individual goals should be reassessed over time based on how a child is responding to treatment and their risk of low blood sugar episodes.
Getting below 7% is a reasonable goal, but it’s not the right number for everyone. Pushing too aggressively toward a lower A1C can increase the frequency of hypoglycemia (blood sugar dropping too low), which carries its own serious risks, especially for older adults.
Targets for Older Adults
Age and overall health significantly shape what counts as a good A1C. The targets loosen as health complexity increases:
- Healthy older adults with a life expectancy of more than 10 years typically aim for an A1C below 7.5%.
- Older adults with significant health conditions or a life expectancy under 10 years may target 8% or below.
- Those with severe illness, cognitive decline, or limited daily function may have an individualized target as high as 8.5%, with the priority being quality of life and avoiding both dangerously high and dangerously low blood sugar.
These higher targets reflect the reality that aggressive blood sugar control in frail or chronically ill patients often causes more harm than benefit. Severe low blood sugar can lead to falls, confusion, and hospitalization, risks that outweigh the long-term benefits of a tighter A1C in someone whose immediate health needs are more pressing.
Targets During Pregnancy
Pregnancy requires tighter blood sugar control than usual. Most guidelines recommend an A1C of 6.5% or lower before becoming pregnant, and below 6% during pregnancy itself. High blood sugar during pregnancy increases the risk of complications for both mother and baby, so the bar is set lower than the standard diabetes target of 7%.
If you’re planning a pregnancy and your A1C is above 6.5%, working to bring it down before conceiving gives you the best starting point for a healthy pregnancy.
When A1C Results Can Be Misleading
Because the A1C test depends on red blood cells, anything that changes how long your red blood cells live or how they behave can throw off the result. Several conditions can cause falsely high or falsely low readings:
- Sickle cell disease and other hemoglobin variants (including hemoglobin C, D, and E) can interfere with certain testing methods, producing inaccurate results.
- Certain types of anemia alter red blood cell lifespan, which skews the measurement.
- Significant kidney disease or liver failure can also affect red blood cell turnover and distort A1C readings.
If you have any of these conditions, your doctor may use alternative methods to track your blood sugar, such as a fructosamine test or continuous glucose monitoring, rather than relying solely on A1C. Hemoglobin variants are particularly common, with hundreds of known types, so if your A1C doesn’t match what your daily glucose readings suggest, this is worth investigating.
How Often to Get Tested
If your A1C is normal and you have no risk factors for diabetes, periodic screening is typically sufficient. For people with prediabetes, testing once a year helps track whether blood sugar levels are stable or trending upward. If you have diabetes and your blood sugar is well controlled on a stable treatment plan, testing twice a year is standard. Those who are adjusting medications or not yet at their target may need testing every three months to see how changes are working.
Since the test reflects a two-to-three-month average, testing more frequently than every three months won’t give you meaningfully new information. The red blood cells carrying the data simply haven’t turned over yet.
What Moves Your A1C
Small, sustained changes in daily habits tend to have a measurable effect on A1C over the course of a few months. Regular physical activity improves your body’s ability to use insulin, which directly lowers average blood sugar. Reducing refined carbohydrates and added sugars prevents the sharp blood sugar spikes that drive A1C up over time. Losing even 5% to 7% of your body weight, if you’re overweight, can be enough to move a prediabetic A1C back into the normal range.
For people already on diabetes medication, consistency matters as much as the medication itself. Skipping doses, irregular meal timing, and poor sleep all contribute to blood sugar variability that shows up in your next A1C reading. If your number isn’t where you want it, the three-month window means that changes you make today will start showing up in your next test.