Eag/A1c Conversion Calculator
If you live with diabetes or prediabetes, you have probably seen two different numbers used to describe your blood sugar: your A1c percentage from a lab test and your estimated average glucose (eAG) in mg/dL or mmol/L. They describe the same thing — your average blood sugar over the past two to three months — but they use completely different units, which can be confusing when your doctor says one and your glucose meter shows the other. An eAG/A1c conversion calculator translates between these two measurements instantly, so you always know what your numbers mean in the units you understand best.
Hemoglobin A1c measures the percentage of your hemoglobin that has glucose attached to it. Because red blood cells live for about three months, this test reflects your average blood sugar over that period. eAG, on the other hand, expresses that same average in the same units you see on a home glucose meter. The conversion comes from a landmark research effort called the ADAG study, which found a reliable linear relationship between A1c and average glucose: eAG (mg/dL) = 28.7 × A1c − 46.7. To get mmol/L, you divide the mg/dL result by 18.015.
Understanding this conversion matters. If your lab report says your A1c is 7.0%, that is the same as an average glucose of about 154 mg/dL. Knowing both forms helps you connect your daily meter readings with your quarterly lab results, set realistic targets with your doctor, and track whether your management plan is actually working.
How to Use the eAG/A1c Conversion Calculator
1. Choose your conversion direction. Select “A1c (%) to eAG (mg/dL)” if you have a lab result and want the glucose equivalent, or “eAG (mg/dL) to A1c (%)” if you have an average glucose number and want the A1c equivalent.
2. Enter your value. Type your A1c percentage (between 4 and 20) or your estimated average glucose (between 40 and 600 mg/dL) into the field that appears.
3. Click Calculate. The calculator instantly converts your number using the standard ADAG formula.
4. Read your result. You will see the converted value — including both mg/dL and mmol/L when converting from A1c — plus a range label of Normal, Prediabetes, or Diabetes.
Worked Example
Suppose Maria just received her lab results and her A1c is 7.0%. She wants to know what that means in the mg/dL units her glucose meter uses.
She selects “A1c (%) to eAG (mg/dL)”, enters 7.0, and clicks Calculate. The calculator applies the formula: 28.7 × 7.0 − 46.7 = 200.9 − 46.7 = 154.2 mg/dL. It also shows the mmol/L equivalent: 154.2 ÷ 18.015 = 8.6 mmol/L. The range label reads Diabetes, since 7.0% is at or above the 6.5% diabetes threshold.
More Helpful Information
The ADAG (A1c-Derived Average Glucose) study monitored hundreds of people with continuous glucose monitors and frequent fingerstick tests, then compared those averages with lab A1c values. The result was a strong linear relationship, captured in the formula eAG = 28.7 × A1c − 46.7. This is the formula endorsed by the American Diabetes Association.
Compare like with like. A single fasting reading is not an average. eAG reflects months of data, so compare it against your meter’s multi-week average, not one morning’s number. Know your unit system. The United States uses mg/dL; most of the rest of the world uses mmol/L.
Frequently Asked Questions
1. What is eAG?
eAG stands for estimated average glucose. It is your average blood sugar level over the past two to three months, expressed in mg/dL or mmol/L instead of the percentage used by A1c.
2. What is the formula to convert A1c to eAG?
The standard formula is eAG (mg/dL) = 28.7 × A1c (%) − 46.7. It comes from the ADAG study and is recommended by the American Diabetes Association.
3. What does an A1c of 7.0% equal in mg/dL?
An A1c of 7.0% converts to an eAG of approximately 154 mg/dL (8.6 mmol/L).
CONCLUSION
Converting between A1c and eAG does not have to involve mental math or memorizing formulas. With our free eAG/A1c conversion calculator, you can instantly translate a lab percentage into the mg/dL or mmol/L numbers you see every day — or go the other way and estimate your A1c from your average glucose. Understanding both sides of your blood sugar picture helps you track progress, communicate better with your doctor, and stay motivated on your health journey.