A1C Calculator

Category: Diabetes
- April 07, 2025
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The A1C test measures your average blood glucose over the past 2-3 months. This calculator helps convert between A1C percentages and estimated Average Glucose (eAG) values.

A1C Calculator

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About A1C Testing

The A1C test (also known as HbA1c, glycated hemoglobin or glycosylated hemoglobin) measures the percentage of hemoglobin proteins in your blood that are coated with glucose. This provides information about your average blood glucose levels over the past 2-3 months.

Understanding A1C Values
  • Below 5.7%: Normal (non-diabetic) range
  • 5.7% to 6.4%: Prediabetes range
  • 6.5% or higher: Diabetes range
  • Target for most people with diabetes: Below 7.0%
A1C to eAG Conversion

The estimated Average Glucose (eAG) helps translate A1C values into the same units used for daily blood glucose monitoring. This makes it easier to compare A1C results with daily glucose measurements.

  • A1C 6.0% ≈ eAG 126 mg/dL (7.0 mmol/L)
  • A1C 7.0% ≈ eAG 154 mg/dL (8.6 mmol/L)
  • A1C 8.0% ≈ eAG 183 mg/dL (10.2 mmol/L)
  • A1C 9.0% ≈ eAG 212 mg/dL (11.8 mmol/L)
Important Notes
  • The relationship between A1C and average glucose can vary between individuals.
  • Certain conditions can affect A1C results, including anemia, hemoglobin variants, and recent blood loss.
  • A1C tests should be performed in a laboratory using NGSP-certified methods for accurate results.
  • Always consult with healthcare providers about your A1C targets and results.

What Is the A1C Calculator?

The A1C Calculator is a practical diabetes management aid that helps you convert between A1C percentages and estimated Average Glucose (eAG) values. Whether you want to understand what your lab-reported A1C means in terms of your daily blood sugar or you’re tracking your glucose levels and want to estimate your A1C, this tool offers quick and clear insights.

By providing either your A1C value or your average blood glucose, you can instantly calculate the corresponding result using a standard medical formula. The calculator supports both mg/dL and mmol/L units, making it helpful no matter which glucose measurement system you use.

Formula Used for Conversion

eAG (mg/dL) = (28.7 × A1C) - 46.7
A1C (%) = (eAG (mg/dL) + 46.7) ÷ 28.7

How to Use the Calculator

The calculator supports two main functions:

  • Convert A1C to Average Glucose: Enter your A1C percentage to see your estimated average glucose levels in mg/dL and mmol/L.
  • Convert Average Glucose to A1C: Input your average blood glucose readings and select the unit. The calculator will estimate your A1C value.

To use it effectively:

  • Select your desired conversion direction.
  • Enter your value (A1C or eAG).
  • Choose the unit if entering glucose (mg/dL or mmol/L).
  • Click "Calculate" to see your results and detailed steps.
  • Use the reset button to start a new calculation.

Why This Calculator Is Useful

This A1C levels tool helps bridge the gap between lab test results and everyday blood sugar monitoring. It's especially helpful for people managing diabetes or prediabetes who want to understand the correlation between A1C and average glucose.

Key benefits include:

  • Quick eAG to A1C conversion for those using daily glucose readings.
  • Blood sugar estimator that’s simple to use and understand.
  • Visual feedback on A1C risk levels, such as normal, prediabetes, or diabetes ranges.
  • Clear explanation of the calculation steps using medically accepted formulas.
  • Helps support better glycemic control and overall glucose monitoring.

Frequently Asked Questions (FAQ)

What is A1C?

A1C (or HbA1c) is a blood test that shows your average blood glucose levels over the past 2 to 3 months. It's commonly used to diagnose and monitor diabetes.

What does eAG mean?

eAG stands for Estimated Average Glucose. It translates your A1C results into the same units you see in daily glucose monitoring—either mg/dL or mmol/L.

Can I convert estimated glucose to A1C?

Yes. Using the calculator’s “Average Glucose to A1C” mode, you can convert eAG to A1C using the standard formula. This is helpful when you track your glucose with a meter or CGM and want to predict your A1C value.

How accurate are the results?

The calculator uses formulas developed from the ADAG (A1C-Derived Average Glucose) study. While they’re accurate for most people, individual results may vary. Always consult your healthcare provider for diagnosis or medical advice.

What do different A1C levels indicate?

  • Below 5.7%: Normal
  • 5.7% to 6.4%: Prediabetes
  • 6.5% and above: Diabetes

Who Can Benefit From This Tool?

This tool is useful for:

  • People with diabetes who want to keep track of their A1C or average glucose.
  • Those using an eAG to A1C Calculator to understand lab results better.
  • Caregivers and healthcare providers who assist patients in managing blood sugar levels.
  • Anyone seeking quick and simple eAG and A1C correlation without doing the math manually.

Explore Related Tools

If you're managing diabetes or monitoring glucose levels regularly, you may also find these calculators helpful:

  • Insulin Dosage Calculator: Calculate insulin needs based on your levels.
  • HOMA-IR Calculator: Assess insulin resistance and HOMA score.
  • QUICKI Calculator: Check insulin sensitivity using the QUICKI index.
  • Glycemic Index Calculator: Measure the impact of foods on blood sugar.
  • Blood Sugar Converter Calculator: Easily switch between mg/dL and mmol/L.
  • Diabetes Risk Calculator: Get a snapshot of your diabetes risk level.

All these tools support better understanding, planning, and control of your glucose levels and overall health.