An A1C test helps you understand what your blood sugar has generally looked like over the past two to three months. Instead of showing your blood sugar at one moment, as a glucose meter does, A1C provides a longer-term picture.
The A1C levels chart below explains which results are generally considered normal, which fall within the prediabetes range and which may indicate diabetes. It also shows the estimated average glucose, or eAG, associated with common A1C percentages.
For most adults who are not pregnant, the commonly used diagnostic ranges are:
- Normal: Below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes range: 6.5% or higher
These ranges are used for screening and diagnosis. They are different from the individual treatment goals set for someone who already has diabetes. The CDC, NIDDK and American Diabetes Association use these thresholds when explaining A1C test results.
Important: An A1C result should be interpreted by a qualified healthcare professional. A single result does not always confirm a diagnosis, particularly when there are no clear symptoms. This page provides general educational information and is not a substitute for medical care.
Quick A1C Levels Chart
| A1C result | General category | Approximate eAG | What it generally means |
|---|---|---|---|
| Below 5.7% | Normal range | Below about 117 mg/dL | The result is below the standard prediabetes threshold |
| 5.7% to 6.4% | Prediabetes range | About 117–137 mg/dL | Blood sugar is higher than normal, but not yet in the diabetes range |
| 6.5% or higher | Diabetes range | About 140 mg/dL or higher | The result meets the laboratory threshold used for diabetes diagnosis |
| Around 7% | Common treatment goal | About 154 mg/dL | A commonly used goal for many adults who already have diabetes |
The last row should not be confused with a diagnostic threshold. An A1C of 7% is not where diabetes begins. Diabetes is generally diagnosed at 6.5% or higher, while a goal below 7% is commonly used for many nonpregnant adults who are already receiving diabetes care. Treatment goals should be individualized.
Detailed A1C to Average Blood Sugar Chart
The following A1C chart converts common A1C percentages into estimated average glucose. The values are estimates and may not exactly match the average shown by a glucose meter or continuous glucose monitor.
| A1C | Estimated average glucose in mg/dL | Estimated average glucose in mmol/L | General interpretation |
|---|---|---|---|
| 4.0% | 68 mg/dL | 3.8 mmol/L | Below prediabetes threshold |
| 4.5% | 82 mg/dL | 4.6 mmol/L | Below prediabetes threshold |
| 5.0% | 97 mg/dL | 5.4 mmol/L | Normal range |
| 5.5% | 111 mg/dL | 6.2 mmol/L | Normal range |
| 5.6% | 114 mg/dL | 6.3 mmol/L | Upper end of normal range |
| 5.7% | 117 mg/dL | 6.5 mmol/L | Prediabetes threshold |
| 6.0% | 126 mg/dL | 7.0 mmol/L | Prediabetes range |
| 6.4% | 137 mg/dL | 7.6 mmol/L | Upper end of prediabetes range |
| 6.5% | 140 mg/dL | 7.8 mmol/L | Diabetes threshold |
| 7.0% | 154 mg/dL | 8.6 mmol/L | Diabetes range |
| 7.5% | 169 mg/dL | 9.4 mmol/L | Diabetes range |
| 8.0% | 183 mg/dL | 10.2 mmol/L | Diabetes range |
| 8.5% | 197 mg/dL | 10.9 mmol/L | Diabetes range |
| 9.0% | 212 mg/dL | 11.8 mmol/L | Diabetes range |
| 9.5% | 226 mg/dL | 12.6 mmol/L | Diabetes range |
| 10.0% | 240 mg/dL | 13.4 mmol/L | Diabetes range |
| 11.0% | 269 mg/dL | 14.9 mmol/L | Diabetes range |
| 12.0% | 298 mg/dL | 16.5 mmol/L | Diabetes range |
| 13.0% | 326 mg/dL | 18.1 mmol/L | Diabetes range |
| 14.0% | 355 mg/dL | 19.7 mmol/L | Diabetes range |
| 15.0% | 384 mg/dL | 21.3 mmol/L | Diabetes range |
The conversion is based on the relationship established by the A1C-Derived Average Glucose study. The commonly used formula is:
The American Diabetes Association uses this formula in its A1C-to-eAG conversion calculator.
Because eAG is an estimate, small differences caused by rounding are normal. Your actual meter or continuous glucose-monitor average may also differ because A1C and home glucose devices do not measure blood sugar in exactly the same way.
What Is an A1C Test?
A1C is a blood test that measures the percentage of hemoglobin with glucose attached to it. Hemoglobin is a protein inside red blood cells that carries oxygen.
Glucose naturally enters the bloodstream after the body breaks down food. Some of this glucose attaches to hemoglobin. When blood sugar remains higher over time, a larger percentage of hemoglobin becomes coated with glucose.
For example, an A1C result of 6% means that approximately 6% of the measured hemoglobin is glycated. It does not mean that 6% of the blood itself is sugar.
Because red blood cells usually remain in circulation for several months, the test can provide an overview of average blood sugar over approximately the previous two to three months. It does not show every high or low blood sugar episode that occurred during that period.
What Is a Normal A1C Level?
An A1C result below 5.7% is generally classified as normal for an adult being screened for prediabetes or diabetes.
Examples of results within this category include:
- 4.8%
- 5.0%
- 5.3%
- 5.6%
A result below 5.7% means it is under the standard laboratory threshold for prediabetes. However, a normal A1C result does not guarantee that a person will never develop diabetes.
A healthcare professional may consider other information, including:
- Fasting blood sugar
- Oral glucose-tolerance results
- Family history
- Age
- Body weight
- Previous gestational diabetes
- Medicines that affect blood sugar
- Symptoms associated with high blood sugar
Different tests do not always identify the same people. Someone may have a normal A1C but an abnormal fasting-glucose or glucose-tolerance result. The reverse can also happen.
What Does an A1C of 5.7% to 6.4% Mean?
An A1C from 5.7% through 6.4% falls within the prediabetes range.
Prediabetes means blood sugar is higher than normal but has not reached the laboratory threshold used to diagnose diabetes. It should not be dismissed simply because it includes the word “pre.”
Prediabetes is associated with a higher risk of developing type 2 diabetes. It is also associated with an increased risk of heart disease and stroke. Within the prediabetes range, a higher result is generally associated with a greater chance of progressing to type 2 diabetes.
Examples include:
| A1C result | General interpretation |
|---|---|
| 5.7% | Beginning of the prediabetes range |
| 5.9% | Prediabetes range |
| 6.0% | Prediabetes range |
| 6.2% | Prediabetes range |
| 6.4% | Upper end of the prediabetes range |
An A1C of 6.2% is not classified as diabetes under the standard diagnostic thresholds. It remains within the prediabetes range.
A clinician may recommend additional testing or monitoring based on the result and the person’s overall risk profile. Lifestyle changes may help reduce the risk of progression, but recommendations should take a person’s medical history, ability and existing treatment into account.
What Does an A1C of 6.5% or Higher Mean?
An A1C result of 6.5% or above falls within the diabetes range.
Examples include:
- 6.5%
- 6.8%
- 7.0%
- 8.0%
- 10.0%
A result in this range does not tell you whether a person has type 1 diabetes, type 2 diabetes or another form of diabetes. Additional clinical evaluation may be needed.
When a person does not have clear symptoms, NIDDK says the diagnosis generally needs to be confirmed with another measurement. This may involve repeating the A1C test on a different day or using another accepted diabetes test. For diagnosis, the blood sample should be analyzed using an appropriate NGSP-certified laboratory method. Point-of-care A1C results should not be used by themselves to diagnose diabetes.
Do not use an online A1C calculator or home glucose reading to diagnose yourself. These tools can help explain numbers, but they cannot replace laboratory testing and professional interpretation.
Diagnostic Range and Treatment Goal Are Not the Same
One of the most common sources of confusion is the difference between an A1C diagnostic threshold and an A1C treatment target.
Diagnostic threshold
The diagnostic threshold is used when testing someone for diabetes:
- Below 5.7%: normal range
- 5.7% to 6.4%: prediabetes range
- 6.5% or higher: diabetes range
Treatment target
A treatment target is used after a person has already been diagnosed with diabetes.
An A1C below 7% is a common goal for many nonpregnant adults with diabetes. However, it is not the right goal for everyone. A healthcare professional may recommend a lower or higher target based on factors such as:
- Age
- Pregnancy
- Duration of diabetes
- Other medical conditions
- Risk of low blood sugar
- Ability to recognize low blood sugar
- Medicines being used
- Personal priorities and treatment burden
This means an A1C of 6.8% is within the diabetes diagnostic range, even though it may also be within the treatment goal selected for a particular person who is already receiving care.
Why Estimated Average Glucose Is Useful
A1C is reported as a percentage, while glucose meters usually display results in mg/dL or mmol/L. Estimated average glucose translates an A1C percentage into familiar glucose units.
For example:
| A1C | Approximate eAG |
|---|---|
| 6% | 126 mg/dL |
| 7% | 154 mg/dL |
| 8% | 183 mg/dL |
| 9% | 212 mg/dL |
| 10% | 240 mg/dL |
This conversion can make an A1C result easier to understand. However, eAG is not a prediction of what your glucose will be at a particular time of day.
Two people with the same A1C may have different daily patterns. One person might have relatively steady readings, while another experiences frequent highs and lows that produce a similar overall average.
A1C also does not show:
- How frequently glucose went too low
- How frequently it went too high
- How long glucose remained in a target range
- Whether glucose rose mainly after meals
- How much readings changed from one day to another
For people using continuous glucose monitoring, time in range and glucose-management information may provide additional context. These measurements should be discussed with a diabetes-care professional rather than treated as interchangeable with laboratory A1C.
When Can an A1C Result Be Inaccurate?
A1C is helpful, but it is not perfect. Anything that changes red-blood-cell lifespan or affects the way hemoglobin is measured can make a result less reliable.
Possible causes of misleading results include:
- Certain types of anemia
- Recent major blood loss
- A recent blood transfusion
- Some hemoglobin variants
- Sickle-cell disease or related conditions
- Pregnancy
- Kidney failure
- Liver disease
- Medicines that affect red-blood-cell production or survival
Some factors may make A1C appear falsely high, while others may make it appear falsely low. The effect can also depend on the testing method used by the laboratory. NGSP maintains information about hemoglobin variants and A1C assay interference.
Speak with a healthcare professional when:
- Your A1C does not match your glucose-meter readings
- Your A1C changes unexpectedly
- You have a known hemoglobin variant
- You recently received a blood transfusion
- You have anemia, kidney disease or another condition affecting blood cells
- The result seems inconsistent with your symptoms
A clinician may use another glucose test or select an A1C method that is less affected by a particular hemoglobin variant.
Do You Need to Fast for an A1C Test?
No fasting is usually needed for an A1C test. You can generally eat and drink normally before the blood sample is collected.
However, a healthcare professional may order other blood tests at the same appointment. Some of those tests may require fasting, so follow the instructions provided by the clinic or laboratory.
What Should You Do After Receiving an A1C Result?
The next step depends on the result, your symptoms, previous test results and your medical history.
Result below 5.7%
Continue following the screening schedule recommended by your healthcare professional. A normal result does not mean that future testing will never be needed.
Result from 5.7% to 6.4%
Arrange a discussion with a healthcare professional. They may confirm the result, review other risk factors or recommend changes that can reduce the chance of developing type 2 diabetes.
Result of 6.5% or higher
Contact a healthcare professional for proper interpretation and confirmatory testing when appropriate. Do not begin, stop or change diabetes medication based only on an online chart.
Seek prompt medical attention when high blood sugar is accompanied by serious symptoms such as vomiting, difficulty breathing, severe weakness, confusion or loss of consciousness.
Frequently Asked Questions
Is an A1C of 5.7% normal?
An A1C of exactly 5.7% is at the beginning of the prediabetes range. A result must be below 5.7% to fall within the standard normal category.
Is an A1C of 6.2% diabetes?
No. Under the standard diagnostic ranges, an A1C of 6.2% is classified as prediabetes. Diabetes begins at an A1C of 6.5% or higher.
Is an A1C of 6.5% automatically a confirmed diabetes diagnosis?
An A1C of 6.5% meets the laboratory threshold for diabetes. However, when clear symptoms are absent, the result generally needs confirmation with a repeat measurement or another accepted diabetes test.
Is an A1C of 7% good?
For many nonpregnant adults who already have diabetes, an A1C below 7% is a common treatment goal. The right target may be different for children, older adults, pregnant people and anyone with a high risk of low blood sugar.
What average blood sugar is equal to an A1C of 7%?
An A1C of 7% corresponds to an estimated average glucose of approximately 154 mg/dL, or about 8.6 mmol/L.
Can I have diabetes with a normal A1C?
It is possible for A1C and other diabetes tests to disagree. Certain medical conditions can also make A1C less reliable. A clinician may order fasting plasma glucose, an oral glucose-tolerance test or another appropriate test when diabetes is still suspected.
Can an A1C test diagnose type 1 diabetes?
A1C can show that blood sugar has been elevated, but it does not determine the type of diabetes. Additional testing, including tests for diabetes-related autoantibodies, may be needed to help identify type 1 diabetes.
Is A1C used to diagnose gestational diabetes?
A1C is not the standard test used to diagnose gestational diabetes. Glucose-challenge and oral glucose-tolerance testing are generally used during pregnancy.
Can a home A1C kit diagnose diabetes?
A home test can provide information, but it should not be used by itself to diagnose diabetes. Diagnosis should be based on suitable laboratory testing and professional interpretation.
Why is my A1C different from my glucose-monitor average?
A1C is a laboratory measurement involving glycated hemoglobin. A glucose monitor measures glucose directly at specific moments, while a continuous monitor estimates glucose in interstitial fluid. Missed readings, differences in red-blood-cell lifespan, hemoglobin variants and natural biological variation can all contribute to differences.
Key Takeaway
The most important numbers in an A1C levels chart are:
- Below 5.7%: Normal range
- 5.7% to 6.4%: Prediabetes range
- 6.5% or higher: Diabetes range
These are general diagnostic categories, not personalized treatment goals. A result should always be interpreted alongside symptoms, medical history and other test results.
Use our A1C calculator to convert your result into estimated average glucose, or view our A1C conversion chart for additional percentages and glucose values.
Medical Disclaimer
This page is intended for general education only. It does not provide a diagnosis, personalized treatment recommendation or emergency medical advice.
A1C values can be affected by pregnancy, anemia, blood loss, transfusions, kidney disease, hemoglobin variants and other factors. Always discuss unexpected or abnormal results with a qualified healthcare professional.
Do not start, stop or change medication based on information from this page.
Sources and Medical References
- Centers for Disease Control and Prevention. Diabetes Testing: A1C Test Ranges. The CDC defines normal A1C as below 5.7%, prediabetes as 5.7%–6.4% and diabetes as 6.5% or above.
- National Institute of Diabetes and Digestive and Kidney Diseases. The A1C Test and Diabetes. Includes diagnostic ranges, confirmation requirements, laboratory-testing guidance and limitations of A1C.
- American Diabetes Association. Diabetes Diagnosis and A1C. Explains standard diagnostic thresholds for normal blood sugar, prediabetes and diabetes.
- American Diabetes Association. eAG/A1C Conversion Calculator. Provides the formula used to convert A1C into estimated average glucose.
- Nathan DM, Kuenen J, Borg R, et al. Translating the A1C Assay Into Estimated Average Glucose Values. Diabetes Care. 2008;31(8):1473–1478.
- NGSP. Factors That Interfere With HbA1C Test Results. Describes hemoglobin variants, red-blood-cell conditions and other factors that can affect A1C accuracy.
- American Diabetes Association. Health Checks for People With Diabetes. Discusses the commonly used A1C goal of below 7% for many adults and the need for individualized targets.