What Is an A1C Calculator?
An A1C calculator is an online tool that helps convert hemoglobin A1C into estimated average glucose, also called eAG. Many people in the United States receive A1C results as a percentage, such as 5.7%, 6.5%, or 7.0%, while daily glucose meters usually show blood sugar in mg/dL. This A1C blood sugar calculator helps connect those two numbers in a simple way.
You can use this hemoglobin A1C calculator as an A1C to average blood sugar calculator, an A1C to eAG calculator, an estimated average glucose calculator, or an average glucose to A1C calculator. It is helpful for understanding the relationship between A1C percentage and average blood sugar, but it should not be used as a medical diagnosis.
How to Use the A1C Calculator
- Choose whether you want to convert A1C to average glucose or average glucose to A1C.
- Enter your A1C percentage, such as 5.6, 6.1, 7.0, or 8.2, or enter your estimated average glucose in mg/dL.
- Optionally enter a target A1C. The calculator uses 7.0% as the default target because it is a common goal for many adults with diabetes, but your personal goal may be different.
- Click the calculate button to see estimated average glucose in mg/dL, estimated average glucose in mmol/L, A1C percentage, A1C category, and a short explanation.
The calculator does not refresh the page and does not store your health information.
A1C to Average Blood Sugar Formula
The A1C to average blood sugar formula used by this A1C mg/dL calculator is:
eAG = (28.7 × A1C) – 46.7
In this formula, eAG means estimated average glucose in mg/dL. For example, an A1C of 7.0% gives an estimated average glucose of about 154 mg/dL.
Average Blood Sugar to A1C Formula
The average glucose to A1C calculator uses the reverse formula:
A1C = (eAG + 46.7) / 28.7
This lets you enter an estimated average glucose value in mg/dL and calculate an estimated A1C percentage. For example, an average glucose of 154 mg/dL is about 7.0% A1C.
What Is Estimated Average Glucose?
Estimated average glucose, or eAG, is a way to express A1C as an average blood sugar number. In the United States, glucose readings are commonly shown in mg/dL. The eAG value can make an A1C percentage easier to understand because it uses the same type of number many glucose meters and lab reports use.
This estimated average glucose calculator also shows mmol/L by dividing mg/dL by 18. Some countries and some medical resources use mmol/L instead of mg/dL.
A1C Ranges Explained
A1C ranges are commonly grouped into normal, prediabetes, and diabetes ranges. These ranges are often used as screening and diagnostic guidelines, but a diagnosis should be made by a qualified healthcare provider using appropriate lab testing and clinical context.
- Below 5.7%: Normal range
- 5.7% to 6.4%: Prediabetes range
- 6.5% or higher: Diabetes range
Normal A1C Range
A normal A1C range is below 5.7%. This means the average blood sugar over the past few months is generally below the prediabetes range. A normal result does not always mean a person has no risk factors, so people should follow their healthcare provider’s advice about future testing, healthy eating, exercise, weight, and family history.
Prediabetes A1C Range
The prediabetes A1C range is 5.7% to 6.4%. Prediabetes means blood sugar is higher than normal but not in the diabetes range. Many people with prediabetes do not notice symptoms, so lab testing can be important. A healthcare provider may suggest lifestyle changes, weight management, physical activity, and follow-up testing.
Diabetes A1C Range
An A1C of 6.5% or higher is commonly considered in the diabetes range. A healthcare provider may repeat testing or use other blood sugar tests to confirm results. If your A1C is in this range, talk with a qualified medical professional about what the result means for you and what steps may be appropriate.
A1C vs Daily Blood Sugar Readings
A1C and daily blood sugar readings are related, but they are not the same. A1C reflects an estimated average over roughly the past two to three months. A glucose meter or continuous glucose monitor can show current readings, daily patterns, highs, lows, and changes after meals, exercise, stress, or medication.
Because A1C is an average, it may not show glucose swings. A person could have highs and lows that average out to the same A1C as someone with steadier readings.
Why Your A1C May Not Match Your Glucose Meter
Your A1C may not perfectly match your glucose meter average for several reasons. Glucose meters measure specific moments in time, while A1C estimates a longer-term average. Testing frequency, timing of checks, meal patterns, exercise, stress, illness, medications, anemia, pregnancy, kidney disease, and some blood conditions may affect results or interpretation.
If your A1C and glucose readings seem very different, bring your meter, logbook, or continuous glucose monitor report to your healthcare provider.
How Often Should A1C Be Checked?
How often A1C should be checked depends on your health history, risk factors, and treatment plan. Some people may be tested yearly or during routine screening. People with diabetes may have A1C checked more often, especially when treatment changes or blood sugar goals are not being met. Your doctor or diabetes care team can recommend a schedule that fits your situation.
Who Can Use This A1C Calculator?
This A1C percentage calculator can be used by adults, caregivers, students, teachers, and anyone who wants to understand A1C conversion. It may be helpful when reading lab results, comparing A1C to estimated average glucose, learning about a normal A1C range, or reviewing an A1C conversion chart.
Limitations of This Calculator
This calculator uses standard conversion formulas, but it is still an estimate. It does not know your medical history, medications, symptoms, pregnancy status, anemia status, kidney function, blood disorders, or other factors that may affect A1C. It also does not replace fasting glucose, oral glucose tolerance testing, continuous glucose monitoring, or professional medical interpretation.
When to Talk to a Doctor
Talk to a doctor, diabetes educator, or qualified healthcare provider if your A1C is in the prediabetes or diabetes range, if your blood sugar readings are often high or low, if you have symptoms such as unusual thirst or frequent urination, or if you are unsure about your results. You should also seek professional guidance before changing medication, diet, insulin, or a diabetes treatment plan.
A1C Chart and A1C Conversion Chart
The A1C chart below shows common A1C percentages converted to estimated average glucose in mg/dL. This A1C conversion chart is useful for quickly comparing A1C percentages with average blood sugar values.
| A1C Percentage |
Estimated Average Glucose |
Approx. mmol/L |
General Category |
| 5.0% |
97 mg/dL |
5.4 mmol/L |
Normal range |
| 5.5% |
111 mg/dL |
6.2 mmol/L |
Normal range |
| 5.7% |
117 mg/dL |
6.5 mmol/L |
Prediabetes range |
| 6.0% |
126 mg/dL |
7.0 mmol/L |
Prediabetes range |
| 6.5% |
140 mg/dL |
7.8 mmol/L |
Diabetes range |
| 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 |
| 10.0% |
240 mg/dL |
13.3 mmol/L |
Diabetes range |
| 11.0% |
269 mg/dL |
14.9 mmol/L |
Diabetes range |
| 12.0% |
298 mg/dL |
16.6 mmol/L |
Diabetes range |
A1C Calculator Examples
Example 1: A1C 5.6% Calculation
Formula: eAG = (28.7 × 5.6) – 46.7 = 114 mg/dL.
An A1C of 5.6% is below 5.7%, so it falls in the normal range. This is an estimate and should be reviewed with your healthcare provider if you have symptoms or risk factors.
Example 2: A1C 6.1% Calculation
Formula: eAG = (28.7 × 6.1) – 46.7 = 128 mg/dL.
An A1C of 6.1% is in the prediabetes range. A healthcare provider may recommend follow-up testing, lifestyle changes, or a prevention plan.
Example 3: A1C 7.0% Calculation
Formula: eAG = (28.7 × 7.0) – 46.7 = 154 mg/dL.
An A1C of 7.0% is in the diabetes range. For many adults with diabetes, 7.0% is a common target, but the right goal depends on the individual.
Example 4: Average Glucose 154 mg/dL to A1C
Formula: A1C = (154 + 46.7) / 28.7 = 7.0%.
An estimated average glucose of 154 mg/dL is about the same as an A1C of 7.0%.
Example 5: Average Glucose 180 mg/dL to A1C
Formula: A1C = (180 + 46.7) / 28.7 = 7.9%.
An estimated average glucose of 180 mg/dL converts to an estimated A1C of about 7.9%.
Frequently Asked Questions
What is an A1C calculator?
An A1C calculator is a tool that estimates average blood sugar from an A1C percentage or estimates A1C from average glucose. It helps explain the relationship between hemoglobin A1C and estimated average glucose.
How do I convert A1C to average blood sugar?
To convert A1C to average blood sugar, use the formula eAG = (28.7 × A1C) – 46.7. The result is estimated average glucose in mg/dL.
What is a normal A1C level?
A normal A1C level is generally below 5.7%. Your healthcare provider can explain what your result means based on your personal health history.
What A1C level means prediabetes?
An A1C from 5.7% to 6.4% is commonly considered the prediabetes range. This means blood sugar is higher than normal but not in the diabetes range.
What A1C level means diabetes?
An A1C of 6.5% or higher is commonly considered in the diabetes range. A diagnosis should be made by a qualified healthcare provider and may require confirmatory testing.
What does eAG mean?
eAG means estimated average glucose. It converts an A1C percentage into an estimated average blood sugar number, usually shown in mg/dL in the United States.
Is A1C the same as daily blood sugar?
No. A1C estimates average blood sugar over the past two to three months, while daily blood sugar readings show glucose at specific moments in time.
Can this calculator diagnose diabetes?
No. This calculator is educational only and cannot diagnose diabetes, prediabetes, or any other medical condition. Talk with a healthcare provider for medical advice and diagnosis.
What is a good A1C goal?
A common A1C goal for many adults with diabetes is around 7.0%, but goals vary. Some people may need a lower or higher target depending on age, health conditions, medications, pregnancy, and risk of low blood sugar.
Why is my A1C different from my glucose meter readings?
A1C is a long-term estimate, while glucose meter readings are moment-by-moment values. Testing times, glucose swings, anemia, pregnancy, certain health conditions, and lab differences can affect how the numbers compare.
How often should A1C be tested?
Testing frequency depends on your health situation. Some people need occasional screening, while people with diabetes may need A1C testing several times per year. Follow your healthcare provider’s recommendation.
Does this calculator store my health information?
No. The calculator runs in your browser and does not save the values you enter.
