What Is a Good A1C Level? Chart by Age and Risk Category

Your A1C tells you how your body has been handling blood sugar over the last 2-3 months. Not a single-morning snapshot like fasting glucose, but the full picture. And unlike a lot of health numbers where "normal" is fuzzy, A1C has sharp cutoffs: normal, prediabetes, diabetes. There's no ambiguity.

Here's what those numbers mean, how they translate to daily blood sugar, and what actually works to bring them down.

A1C Ranges: Normal, Prediabetes, and Diabetes

A1C measures what percentage of your hemoglobin (the protein in red blood cells that carries oxygen) is sugar-coated. More sugar in your blood means more coated hemoglobin. The ADA thresholds:

These cutoffs come from population studies showing that complications (especially eye damage) spike above 6.5%. The prediabetes range of 5.7-6.4% is where you have the most power to change things, and where the conversation should start.

A1C to Average Blood Sugar Conversion

The most useful thing you can do with your A1C is convert it to an average blood sugar you can actually picture. The formula, validated by the A1C-Derived Average Glucose (ADAG) study, is:

eAG (mg/dL) = (28.7 x A1C) - 46.7

You can run this conversion instantly with the A1C Calculator, which works in both directions: enter an A1C to get eAG, or enter a blood sugar reading to see the equivalent A1C.

What Affects A1C Accuracy?

A1C is reliable for most people. But a few things can throw it off, and getting treated for a number that's wrong is a real problem.

Hemoglobin variants. Sickle cell trait and others can mess with certain A1C tests. If you have one, make sure your lab knows.

Anemia and blood loss. Iron deficiency, B12 deficiency, or recent blood loss makes red blood cells turn over faster, giving them less time to accumulate sugar. Your A1C looks better than it should.

Kidney disease. Chronic kidney disease can cause falsely elevated A1C levels. Your doctor may use fructosamine testing as an alternative if kidney function is impaired. The eGFR Calculator can help you estimate your kidney function from a basic metabolic panel.

Recent blood transfusions. A transfusion introduces red blood cells with a different glycation history, which can make the A1C unreliable for about 3 months afterward.

If your A1C doesn't match how your daily glucose readings look or how you feel, bring it up with your doctor. For a broader overview of what all your lab numbers mean, see our guide to reading blood test results.

A1C Targets by Age and Situation

Below 5.7% is "normal" for everyone. But if you have diabetes, the right target depends on your age, health, and circumstances.

For Most Adults With Type 2 Diabetes

The ADA target: below 7.0% for most adults. Reduces nerve, eye, and kidney damage risk without pushing blood sugar so low you pass out.

For Younger Adults and Those Without Complications

Younger patients recently diagnosed can aim for below 6.5% if they can hit it without constant lows. With decades ahead, tight control pays off the most over time.

For Older Adults (65+)

Below 8.0% for older adults with multiple health issues or history of dangerous lows. At 75, crashing your blood sugar and falling is a more immediate threat than running slightly high.

During Pregnancy

Pregnant women with pre-existing diabetes should aim for an A1C of below 6.0% if it can be achieved without significant hypoglycemia. Elevated blood sugar during pregnancy increases the risk of birth defects, preeclampsia, and macrosomia (an overly large baby). Track your pregnancy timeline with the Due Date Calculator.

Prediabetes: The Most Important Range

5.7-6.4% is where the magic happens, if you actually do something about it. Research from the landmark Diabetes Prevention Program (DPP) trial showed that lifestyle intervention reduced the risk of developing Type 2 diabetes by 58% in people with prediabetes, outperforming the medication metformin (which reduced risk by 31%).

The changes that worked weren't extreme. Lose 7% of your body weight (14 pounds if you weigh 200) and walk briskly for 150 minutes a week. That's it. No keto. No CrossFit. Just moderate weight loss and regular walking.

If you're prediabetic, this is one of the best pieces of health news you can get. It sounds backwards, but it means you caught it early enough to reverse it. The window is open. Modest changes produce real results.

Evidence-Based Ways to Lower Your A1C

1. Moderate Weight Loss

Losing 5-10% of your body weight is one of the most effective things you can do for blood sugar. At 200 pounds, that's 10-20 pounds. You don't need to hit your "ideal weight." Even partial loss makes a measurable difference in insulin sensitivity. Use the BMI Calculator to establish your starting point, and the Calorie Calculator to find a sustainable calorie target.

2. Regular Physical Activity

Exercise helps even if you don't lose a pound. Walking, cycling, swimming, lifting weights -- all of it improves insulin sensitivity. 150 minutes per week of moderate activity plus resistance training twice a week is the evidence-based target. And walking after meals specifically blunts the blood sugar spike that follows eating. It's one of the simplest interventions and one of the most effective. Track your daily movement with the Step Calorie Calculator.

3. Dietary Changes

There's no single "diabetes diet." But the eating patterns that consistently lower A1C all share traits: lots of fiber (vegetables, beans, whole grains), moderate protein, less refined carbs and sugar, healthy fats. Mediterranean, DASH, and moderate low-carb all work. Pick the one you'll actually stick with.

The single biggest change for most people: stop drinking sugar. Soda, juice, sweet tea, fancy coffee drinks. Liquid sugar dumps glucose into your bloodstream without making you feel full. It's the worst possible way to consume calories if you're managing blood sugar. The Macro Calculator can help you set targets for carbs, protein, and fat.

4. Sleep and Stress Management

Sleeping under 6 hours regularly is directly linked to higher A1C. Chronic stress does the same thing through cortisol. Both wreck your insulin sensitivity. Getting 7-9 hours of real sleep and managing stress (however you do it -- exercise, meditation, therapy, whatever works) creates the foundation that makes everything else work better. Check your sleep habits with the Sleep Calculator.

5. Medication When Needed

If lifestyle changes aren't enough (or your diabetes is already established), medication fills the gap. Metformin is the standard first-line drug with decades of safety data. The newer GLP-1 drugs (Ozempic/semaglutide, Mounjaro/tirzepatide) have been impressive for both A1C and weight loss. Talk to your doctor about what makes sense for you.

How Often Should You Test A1C?

For people with normal A1C (below 5.7%): screening every 3 years is typical, or annually if you've risk factors like family history, obesity, or a history of gestational diabetes.

For prediabetes (5.7-6.4%): annual testing is recommended to track whether your interventions are working and whether you've progressed toward diabetes.

For diabetes: the ADA recommends A1C testing at least twice per year for people meeting treatment goals, and quarterly for those whose therapy has changed or who aren't meeting targets.

A1C vs. Other Blood Sugar Tests

Your doctor might order several blood sugar tests. Here's how they're different:

Fasting blood glucose measures your blood sugar after an overnight fast. Normal is below 100 mg/dL, prediabetes is 100-125, and diabetes is 126+. It captures a single moment in time.

Oral glucose tolerance test (OGTT) measures blood sugar two hours after drinking a glucose solution. It's more sensitive than fasting glucose for detecting prediabetes but is less commonly used because it's more inconvenient.

A1C reflects average blood sugar over 2-3 months. It doesn't require fasting and is less affected by day-to-day variability. However, it can be less accurate in the conditions described above.

Continuous glucose monitors (CGMs) provide real-time blood sugar data and are increasingly used by people with and without diabetes. They show patterns that A1C cannot, such as post-meal spikes and overnight drops. However, they're more expensive and not always covered by insurance for non-diabetic use.

For a comprehensive view of all your lab results, including A1C, fasting glucose, and metabolic panels, check out our guide to reading blood test results and the Lab Results Interpreter.

Sources

American Diabetes Association: ADA Standards of Care 2025: A1C diagnostic criteria and treatment targets
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): A1C test overview and accuracy considerations
Diabetes Prevention Program Research Group: Landmark DPP trial showing 58% risk reduction with lifestyle intervention

Related Tools

Convert your A1C with the A1C Calculator. Check your BMI with the BMI Calculator. Estimate your calorie needs with the Calorie Calculator. Set macronutrient targets with the Macro Calculator. Estimate kidney function with the eGFR Calculator. Interpret all your lab numbers with the Lab Results Interpreter. And explore cardiovascular risk with the CT Calcium Score Calculator.