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

Your A1C is one of the most important numbers in preventive medicine. It tells you and your doctor how well your body has been managing blood sugar over the past 2-3 months. Unlike a single fasting glucose reading, which captures a snapshot in time, the A1C reflects the bigger picture. And unlike many health metrics, the A1C thresholds are remarkably clear: there are well-defined cutoffs for normal, prediabetes, and diabetes.

This guide explains what those numbers mean, how they translate to average blood sugar, and what you can realistically do to move your A1C in the right direction.

A1C Ranges: Normal, Prediabetes, and Diabetes

The A1C test measures the percentage of your hemoglobin (a protein in red blood cells) that is coated with sugar. Higher blood sugar means more coated hemoglobin. The standard diagnostic thresholds, established by the American Diabetes Association, are:

These cutoffs are not arbitrary. They are based on large population studies showing that the risk of diabetic complications (particularly retinopathy) rises sharply above an A1C of 6.5%. The prediabetes range of 5.7-6.4% is the zone where intervention has the greatest impact, and it is where the conversation should start.

A1C to Average Blood Sugar Conversion

The most practical way to understand your A1C is to convert it to an estimated average glucose (eAG). 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?

The A1C test is reliable for most people, but several factors can cause misleading results. Understanding these is important because a falsely high or low A1C could lead to inappropriate treatment.

Hemoglobin variants. Sickle cell trait, hemoglobin C, and other hemoglobin variants can interfere with certain A1C testing methods. If you have a known hemoglobin variant, make sure your lab uses a testing method that accounts for it.

Anemia and blood loss. Conditions that affect red blood cell turnover, such as iron-deficiency anemia, vitamin B12 deficiency, or recent blood loss, can falsely lower A1C results. If your red blood cells are being replaced faster than normal, they have less time to accumulate sugar, making the A1C look artificially good.

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 result seems inconsistent with your daily glucose readings or how you feel, discuss these factors 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

The "right" A1C target is not the same for everyone. While below 5.7% is the definition of normal, the clinical targets for people with diabetes vary based on age, health status, and risk factors.

For Most Adults With Type 2 Diabetes

The American Diabetes Association recommends a target A1C of below 7.0% for most non-pregnant adults. This level has been shown to reduce the risk of microvascular complications (nerve, eye, and kidney damage) while keeping the risk of dangerous low blood sugar (hypoglycemia) acceptably low.

For Younger Adults and Those Without Complications

More aggressive targets of below 6.5% may be appropriate for younger patients who are early in their diabetes diagnosis, have a long life expectancy, and can achieve tighter control without frequent hypoglycemia. These patients have the most to gain from long-term A1C reduction.

For Older Adults (65+)

Guidelines from the ADA and other organizations suggest a more relaxed target of below 8.0% for older adults, particularly those with multiple chronic conditions, limited life expectancy, or a history of severe hypoglycemia. The risks of aggressive glucose control (falls from dizziness, confusion, hospitalization for low blood sugar) can outweigh the benefits in this population.

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

An A1C of 5.7-6.4% is the zone where you have the most power to change your trajectory. 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 lifestyle interventions that moved the needle in the DPP were not extreme. They involved moderate weight loss (7% of body weight, which is about 14 pounds for a 200-pound person) and 150 minutes per week of moderate physical activity (like brisk walking). That is it. No special diet, no intense exercise regimen.

If your A1C is in the prediabetic range, this is genuinely one of the most actionable health findings you can get. The window for reversal is open, and relatively modest changes produce significant 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 ways to improve insulin sensitivity and lower A1C. For a 200-pound person, that is 10-20 pounds. You do not need to reach an ideal BMI; even partial weight loss makes a measurable difference. Use the BMI Calculator to establish your starting point, and the Calorie Calculator to find a sustainable calorie target.

2. Regular Physical Activity

Exercise improves insulin sensitivity independently of weight loss. Both aerobic exercise (walking, cycling, swimming) and resistance training (weights, bodyweight exercises) are effective. The current evidence supports at least 150 minutes per week of moderate activity, with resistance training at least twice per week. Walking is underrated: regular walking after meals specifically helps blunt post-meal blood sugar spikes. Track your daily movement with the Step Calorie Calculator.

3. Dietary Changes

No single "diabetes diet" is universally recommended, but the patterns that consistently improve A1C share common features: they are high in fiber (vegetables, legumes, whole grains), moderate in protein, lower in refined carbohydrates and added sugars, and include healthy fats. The Mediterranean diet, DASH diet, and moderate low-carb approaches all have evidence supporting A1C improvement.

The most impactful single change for many people is reducing liquid sugar. Soda, fruit juice, sweetened coffee drinks, and sweet tea can add massive glucose loads without triggering the satiety signals that solid food provides. The Macro Calculator can help you set targets for carbs, protein, and fat.

4. Sleep and Stress Management

Poor sleep and chronic stress both increase insulin resistance and cortisol levels, directly worsening blood sugar control. Studies show that consistently getting fewer than 6 hours of sleep is associated with higher A1C levels. Prioritizing 7-9 hours of quality sleep and managing stress through whatever works for you (exercise, meditation, social connection, therapy) creates a foundation that makes all the other interventions more effective. Check your sleep habits with the Sleep Calculator.

5. Medication When Needed

For people with diagnosed diabetes or high-risk prediabetes, medication may be appropriate alongside lifestyle changes. Metformin is the most common first-line medication for Type 2 diabetes and has a strong safety profile. Newer medications like GLP-1 receptor agonists (semaglutide, tirzepatide) have shown impressive A1C reductions along with weight loss benefits. Medication decisions should always be made in partnership with your doctor.

How Often Should You Test A1C?

For people with normal A1C (below 5.7%): screening every 3 years is typical, or annually if you have 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 have 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 are not meeting targets.

A1C vs. Other Blood Sugar Tests

Your doctor may order several different blood sugar tests, and it helps to understand how they differ.

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 is more sensitive than fasting glucose for detecting prediabetes but is less commonly used because it is more inconvenient.

A1C reflects average blood sugar over 2-3 months. It does not 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 are 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.

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.