Estimated average glucose, or eAG, is a number that translates your A1C test result into the same units you see on a blood glucose meter. Instead of a percentage, eAG gives you a blood sugar average in mg/dL (or mmol/L), making it much easier to connect your lab results to what you see when you check your blood sugar at home. If your A1C is 7%, for example, your eAG is roughly 154 mg/dL, meaning your blood sugar averaged around that level over the previous two to three months.
How eAG Is Calculated
eAG isn’t a separate blood test. It’s a mathematical conversion of your A1C result using a formula established by the A1C-Derived Average Glucose (ADAG) study. That study, published in 2008, followed 507 people across 10 centers in the U.S., Europe, and Africa. The participants included 268 people with type 1 diabetes, 159 with type 2 diabetes, and 80 people without diabetes. Researchers compared each person’s A1C with frequent blood sugar readings over three months to map the relationship between the two numbers.
The formula that came out of the study is: eAG (mg/dL) = 28.7 × A1C − 46.7. So for an A1C of 6%, the eAG is about 126 mg/dL. At 8%, it’s roughly 183 mg/dL. Your lab report may list eAG right alongside your A1C, or your doctor may mention it during your visit.
Why eAG Exists
A1C is reported as a percentage, which can feel abstract. If your meter reads 140 or 180 on a given day, hearing that your A1C is “7.2%” doesn’t immediately tell you whether those daily readings are tracking well. eAG bridges that gap by putting your long-term average into the same mg/dL scale your meter uses. It makes it easier to spot patterns: if your daily readings hover around 150 but your eAG comes back at 183, that’s a sign your blood sugar is spending more time elevated than your spot checks suggest, possibly overnight or after meals you aren’t testing.
The American Diabetes Association adopted eAG reporting to help people with diabetes have more productive conversations with their care teams about blood sugar management. It turns a lab abstraction into a number that feels concrete and comparable to everyday monitoring.
eAG vs. Daily Glucose Readings
Your meter or continuous glucose monitor shows what your blood sugar is doing right now, or at the specific moment you prick your finger. eAG, on the other hand, reflects an average over roughly 8 to 12 weeks, because A1C measures how much sugar has attached to your red blood cells over their lifespan. Both numbers matter, but they answer different questions. A single meter reading tells you whether you need to act in the moment. eAG tells you how well your overall management strategy is working.
One important thing to keep in mind: eAG is an average, so it can hide extremes. Two people could have the same eAG of 154 mg/dL, but one might have very stable blood sugar throughout the day while the other swings between 70 and 250. If you use a continuous glucose monitor, metrics like time in range give you a fuller picture of variability that eAG alone can’t capture.
Common eAG Values and What They Mean
Here’s how A1C percentages translate to eAG, so you can quickly compare your lab results with your day-to-day readings:
- A1C 5.0%: eAG of about 97 mg/dL
- A1C 5.7%: eAG of about 117 mg/dL (upper limit of normal; prediabetes begins here)
- A1C 6.0%: eAG of about 126 mg/dL
- A1C 6.5%: eAG of about 140 mg/dL (diabetes diagnosis threshold)
- A1C 7.0%: eAG of about 154 mg/dL (common management target)
- A1C 8.0%: eAG of about 183 mg/dL
- A1C 9.0%: eAG of about 212 mg/dL
- A1C 10.0%: eAG of about 240 mg/dL
For most adults with diabetes, a target A1C below 7% (eAG below 154 mg/dL) is commonly recommended, though individual goals can vary based on age, other health conditions, and how long a person has had diabetes.
When eAG May Be Inaccurate
Because eAG is derived entirely from your A1C, anything that throws off the A1C test will throw off eAG too. Several conditions can do this.
Any condition that shortens the lifespan of red blood cells will make A1C (and therefore eAG) falsely low. This includes hemolytic anemia, significant blood loss, and chronic kidney disease requiring dialysis. When red blood cells are destroyed or replaced faster than usual, sugar has less time to accumulate on them, so the test underestimates your true average blood sugar.
Iron deficiency anemia pulls the result in the opposite direction, making A1C and eAG falsely high. This is especially relevant during late pregnancy, when iron deficiency is common. Even in people without diabetes, iron deficiency can push A1C readings up enough to cause confusion. Once the iron deficiency is treated, the numbers typically come back down.
Hemoglobin variants, which are genetic differences in the structure of hemoglobin, can also interfere. People with sickle cell disease (HbSS), hemoglobin C disease (HbCC), or combinations like HbSC face a double problem: the hemoglobin variant itself may affect the lab assay, and the associated anemia and increased red cell turnover further distort the result. For these individuals, alternative tests that measure sugar attached to other blood proteins offer a more reliable picture of long-term blood sugar control.
If you have any of these conditions and your eAG doesn’t seem to match what your meter or continuous glucose monitor is showing, the discrepancy is likely in the A1C, not in your daily readings.
How to Use Your eAG
The most practical way to use eAG is as a reality check. Compare it to the averages displayed on your glucose meter or continuous glucose monitor. If the numbers are close, your monitoring routine is likely capturing a good representation of your blood sugar throughout the day. If your eAG is noticeably higher than your meter average, you may be missing highs, often after meals or during sleep, that aren’t showing up in your spot checks.
Tracking eAG over multiple lab visits also helps you see long-term trends. A drop from 183 to 154 mg/dL over six months is a clearer, more intuitive signal of progress than watching your A1C move from 8% to 7%, even though the two are saying exactly the same thing. That’s the whole point of eAG: it takes a useful but opaque lab metric and makes it feel like a number you already understand.