What Your Estimated Average Glucose Means

Calculating eAG to Improve Diabetes Management

Estimated average glucose (eAG) is an estimate of your average blood sugar (glucose) levels over two to three months. It indicates how well you are controlling your diabetes.

The eAG number is useful in diabetes management because it gives you the big picture of where you've been for the past couple of months.

This article discusses what estimated average glucose is, how it is calculated, and what it means for your diabetes care.

Person undergoing a blood test
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What Is Estimated Average Glucose?

Your estimated average glucose (eAG) gives you an idea of your blood glucose levels for the last two to three months. Also known as an average glucose level, eAG translates your A1C blood test results from a percent into milligrams per deciliter (mg/dL). This is the same unit used in home blood glucose monitors.

Understanding your eAG can help improve your diabetes management. Your eAG is useful because it is expressed in the same units as your blood glucose monitor results. This allows you to more easily compare the average of where you've been for the last two months with where your glucose levels are at a given moment in a home reading.

How eAG Is Calculated

Both A1C testing and daily glucose readings provide useful information for managing diabetes, but they are expressed in different ways. Daily glucose meter readings are a direct measurement of the amount of glucose in your blood at the time a sample is taken and is expressed as milligrams of glucose per deciliter of blood—for example, 154 mg/dL.

A1C also uses a blood sample, but it looks at the percentage of hemoglobin, a protein in red blood cells, that has glucose attached to it (glycated hemoglobin). This reveals what an individual's average blood glucose level has been for the past two to three months. An A1C of 7% means that 7% of the total hemoglobin in a blood sample is glycated.

The eAG is determined using a straightforward mathematical formula that converts percentage of glycated hemoglobin as determined by an A1C test into the unit you're used to seeing on your glucometer: mg/dL: 28.7 × A1C – 46.7 = eAG.

Knowing your eAG can help with diabetes management by:

  • Confirming self-monitoring tests or practitioner-ordered blood tests
  • Providing an overall look at how a treatment plan is working
  • Illuminating how healthy lifestyle choices can impact blood sugar control

A1C and eAG levels will differ depending on several factors, including age, sex, activity level, etc. The ADA recommends a target eAG of 154 mg/dL (A1C = 7%) for most adults with diabetes who are not pregnant.

Your eAG number won't match your daily glucose readings exactly. Your eAG isn't just one single reading at one point in time. Instead, it's an average over a long period of time. It shows you how well your long-term strategies are working instead of where your glucose levels are at the moment.

A high eAG means that your glucose levels have been higher than normal for the past two or three months. High average glucose levels are related to diabetes complications.

A1C and eAG Equivalents At-a-Glance
A1C (percentage) eAG (mg/dL)
6.0% 126 mg/dL
6.5% 140 mg/dL
7.0% 154 mg/dL
7.5% 169 mg/dL
8.0% 183 mg/dL
8.5% 197 mg/dL
9.0% 212 mg/dL
9.5% 226 mg/dL
10.0% 240 mg/dL

A1C/eAG vs. Daily Monitoring

While A1C/eAG values are important for long-term diabetes management, they can’t replace daily blood glucose tests. Neither is indicative of current blood sugar levels. You need that information one or more times a day in order to adjust your insulin dose, food intake, and activity level.

The American Diabetes Association recommends that you get an A1C test twice a year if you are meeting glycemic goals and at least every three months (and as needed) if your therapy recently changed and/or you are not meeting treatment goals.

EAG vs. Blood Glucose Meter Average

Most blood glucose meters used for daily testing can provide an average of all readings over the past several weeks or months. This average is not the same as the eAG. Even if you test your blood 10 times a day or more, you are only getting a reading of what your glucose is at that moment.

The average determined by your glucose meter is likely to be either lower or higher than your eAG:

  • If you measure sugar only postprandially (after you eat), eAG will be lower than meter sugar.
  • If you measure sugar only preprandially (before you eat), eAG may be higher than meter sugar.

This happens because the eAG represents an average of your glucose levels 24 hours a day and over a much longer period of time. Therefore, eAG provides a more accurate bigger picture.

By combining your eAG number with your glucose meter’s average number, you are getting a valuable and comprehensive picture of your overall diabetes management. This will help you make healthy goals and choices to achieve appropriate glucose control.

Summary

Your estimated average glucose (eAG) can help you better manage diabetes because it gives you the big picture. It is calculated from your A1C results and shows where your average glucose has been for the last two or three months.

Testing your blood sugar levels via any method can trigger strong feelings. Be gentle with yourself and remember that you are not a number. Make sure you have a supportive care team to help you reach your treatment plan goals, adjusting as needed without judgment.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Diabetes and Digestive and Kidney Diseases. The A1C test & diabetes.

  2. Sherwani SI, Khan HA, Ekhzaimy A, et al. Significance of HbA1c test in diagnosis and prognosis of diabetic patientsBiomark Insights. 2016;11:95–104. doi:10.4137/BMI.S38440

  3. American Diabetes Association. Diabetes Pro. eAG/A1C Conversion Calculator.

  4. MedlinePlus. Estimated average glucose (eAG).

  5. American Diabetes Association Professional Practice Committee. 6. Glycemic targets: Standards of medical care in diabetes—2022Diabetes Care. 2022;45(Supplement_1):S83-S96. doi:10.2337/dc22-S006

  6. Centers for Disease Control and Prevention. All about your A1C.

Additional Reading

By Gary Gilles
Gary Gilles is a licensed clinical professional counselor (LCPC) who has written about type 1 diabetes and served as a diabetes counselor. He began writing about diabetes after his son's diagnosis as an infant.