A good HbA1c is below 5.7%, which falls in the normal range for someone without diabetes. If you already have diabetes, the target shifts higher, typically between 7% and 8% depending on your age and overall health. Understanding where you fall on this scale, and what your number actually means, helps you gauge how well your body is managing blood sugar over time.
What the A1c Ranges Mean
The A1c test measures the percentage of your red blood cells that have glucose attached to them. Three standard ranges are used for diagnosis:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher
If your result comes back at 5.4%, for example, your blood sugar management is in a healthy place. A result of 5.9% puts you in the prediabetes zone, which means your blood sugar is elevated enough to warrant attention but hasn’t crossed the diabetes threshold. At 6.5% or above, the result typically confirms a diabetes diagnosis, though your doctor will usually repeat the test or combine it with other blood sugar tests to be sure.
Why the Test Reflects 2 to 3 Months
Glucose in your bloodstream sticks to hemoglobin, the protein inside red blood cells that carries oxygen. This binding happens continuously and can’t be reversed, so once a red blood cell picks up glucose, it stays attached for the life of that cell. Red blood cells survive about 120 days before your body replaces them, which is why the A1c captures a rolling average of your blood sugar rather than a single moment.
The average isn’t evenly weighted across those months, though. Roughly half of the glycation reflected in your A1c happened in the most recent 30 days. Another 40% comes from days 31 through 90, and only about 10% from anything older than 90 days. So recent changes in your diet, medication, or activity level will influence your next A1c more than changes you made three months ago.
A1c Targets if You Have Diabetes
For people already diagnosed with diabetes, “good” doesn’t mean getting back below 5.7%. Clinical guidance from the American College of Physicians recommends a target of 7% to 8% for most adults with type 2 diabetes. Pushing below 7% hasn’t been shown to reduce the risk of death or major cardiovascular events like heart attack and stroke, and aggressive blood sugar lowering can increase the risk of dangerous low blood sugar episodes.
A stricter target, closer to 7%, may be reasonable if you’re younger and expected to live at least another 15 years, since keeping blood sugar tighter over decades can reduce long-term damage to small blood vessels in the eyes, kidneys, and nerves. For older adults, especially those over 80 or living with multiple chronic conditions, treatment focuses more on relieving symptoms of high blood sugar than on hitting a specific A1c number. Tight control in this group tends to cause more harm than benefit.
How A1c Translates to Daily Blood Sugar
Your A1c percentage corresponds to an estimated average glucose level, which can make the number feel more concrete if you’re used to checking blood sugar with a finger stick or continuous monitor. The conversion formula is straightforward: multiply your A1c by 28.7, then subtract 46.7. Here are some common benchmarks:
- 6.0% = about 126 mg/dL average
- 7.0% = about 154 mg/dL average
- 8.0% = about 183 mg/dL average
- 9.0% = about 212 mg/dL average
- 10.0% = about 240 mg/dL average
Keep in mind this is an average. Two people with the same A1c of 7.0% could have very different daily patterns. One might hover steadily around 154 mg/dL, while the other swings between 80 and 250 throughout the day. That’s why many clinicians now pair A1c results with continuous glucose monitoring data to get a fuller picture of blood sugar stability.
When the A1c Can Be Misleading
Because the test depends on red blood cells lasting their full lifespan, anything that changes how long your red blood cells survive will skew the result. Conditions that destroy red blood cells faster than normal, like hemolytic anemia, recent significant blood loss, or sickle cell disease, will make your A1c look falsely low. Your body is replacing red blood cells more quickly, so they have less time to accumulate glucose.
Iron deficiency anemia pushes the result in the opposite direction. It’s associated with falsely elevated A1c readings, even in people without diabetes. This is especially relevant during late pregnancy, when iron deficiency is common and can raise A1c readings in otherwise non-diabetic women. Once iron deficiency is treated, A1c levels tend to drop back down.
Chronic kidney disease, particularly in people on dialysis, also complicates the picture. A1c tends to underestimate actual blood sugar levels in these patients. For anyone with these conditions, alternative measures like direct glucose monitoring or glycated albumin testing give a more reliable view of blood sugar control.
Certain hemoglobin variants, including sickle cell trait and hemoglobin C trait, can also interfere with some testing methods. If you carry one of these traits, your doctor may need to use a specific lab method or rely on other tests altogether.
A1c Targets During Pregnancy
Pregnancy has its own set of guidelines. For women with pre-existing diabetes who are planning to become pregnant, the recommended A1c target is below 6.5% before conception, provided this doesn’t cause frequent low blood sugar episodes. At an A1c above 10%, the risk of serious complications for both mother and baby is high enough that clinical guidelines from the UK’s National Institute for Health and Care Excellence strongly advise delaying pregnancy until the number comes down.
During pregnancy itself, blood sugar targets are typically managed through frequent glucose monitoring rather than A1c alone, because the rapid changes in blood volume and red blood cell turnover during pregnancy can make A1c less reliable.
What Moves Your A1c
If your A1c is higher than you’d like, the same factors that affect daily blood sugar are what shift the number over time: what you eat, how active you are, stress levels, sleep quality, and (if prescribed) medication adherence. Because the test is weighted toward the most recent month, consistent changes over four to six weeks will start showing up in your next result.
Small, sustained shifts tend to matter more than dramatic short-term efforts. Replacing refined carbohydrates with fiber-rich foods, walking after meals, and getting consistent sleep are the changes most likely to nudge the number down gradually. The 2025 ADA Standards of Care also emphasize evidence-based eating patterns that prioritize plant-based proteins, fiber, and overall nutrient quality, along with resistance training for people using weight management medications or who have had metabolic surgery.
Your A1c is best understood as a trend line, not a single verdict. One reading tells you where you’ve been recently. Two or three readings over the course of a year tell you whether you’re moving in the right direction.