The A1C test measures blood sugar management over 2 or 3 months. To estimate an A1C, clinicians may use an estimated average glucose (eAG) to help people with diabetes better understand how this multi-month average compares to blood sugar readings from finger-stick meters at home.

The hemoglobin A1C test is a way to get a more complete picture of blood sugar levels over the past few months or so.

Doctors’ offices report this A1C result as a percentage.

But in recent years, a new standard known as the estimated average glucose (eAG) has entered the diabetes world. This standard was meant to better translate A1C results into a common measurement, the milligrams per deciliter (mg/dL) readings that people with diabetes see daily on their home finger-stick meters.

The idea is to help people with diabetes better understand how their diabetes management is going and what actions they might need to take based on their A1C and eAG results.

This number is not the same average that someone may see on their home meter, even though it’s also reflected in mg/dL.

That’s because people with diabetes might test at specific times of day, such as when they first wake up or before they eat breakfast. But they might not test throughout the day or night, meaning that those meter averages may not reflect other high or low blood sugar numbers that they might experience during the day or night.

The eAG is meant to reflect those unknown factors in glucose averages over a 24-hour period.

Based on the 2008 research that led to the creation of eAG, the diabetes clinical community adopted a mathematical formula for determining eAG and estimated A1C.

The relationship between A1C and eAG is described by the formula 28.7 x A1C – 46.7 = eAG.

In other words, multiply an A1C result by 28.7 and then subtract 46.7 from that number. The result is the person’s eAG.

  • 6.5% A1C = 140 mg/dL eAG
  • 7% A1C = 154 mg/dL eAG
  • 9% A1C = 211 mg/dL eAG

The American Diabetes Association suggests an A1C of 7% for nonpregnant adults, which is an eAG of 154 mg/dL, but more or less stringent glycemic goals may be appropriate for each individual.

Always make sure to discuss A1C and blood sugar management with a doctor or another healthcare professional. They can best advise people with diabetes on what glucose ranges may be best and what that might mean in the relationship to A1C results and eAG numbers.

The American Diabetes Association’s yearly Standards of Care define specific recommended ranges for people with diabetes, but each person can work with their diabetes care team to establish a personal target.

This article is not meant to be diagnostic or replace medical advice, and specific test results may be different for each person and may not match what is discussed with medical professionals.

People with diabetes may calculate an A1C to see how their blood sugar numbers compare to the 2- or 3-month average that may show on a clinical lab test.

The eAG is one way to help translate those A1C numbers into the same measurement used on finger-stick glucose meters. This eAG has been shown to benefit people and help them better understand how the result relates to their diabetes management.

While a mathematical formula calculates this eAG, it’s always best to consult a diabetes care professional to understand what the results may mean in the context of someone’s diabetes management plan.