Estimated Average Glucose (eAG)
Estimated average glucose is your HbA1c spoken in the language of a glucose meter. No glucose was measured to produce it, which is why it almost never matches the average on your meter.
Part of the Diabetes Panel — see all 9 values together, including Beta-Hydroxybutyrate, Glycated Albumin, Hemoglobin A1c.
A number appears on the lab report under your HbA1c, written in mg/dL, looking exactly like something a glucose meter spat out. It wasn't. No drop of blood was tested for sugar to produce that figure. The lab took your HbA1c and ran it through a formula, then printed the answer in the units a meter speaks so the result would feel familiar. That translated figure is the estimated average glucose, or eAG.
Think of it as a currency conversion. Your HbA1c is the amount, quoted in percent, the way one country prices things. The eAG is that identical amount restated in another currency, mg/dL, for people who think in glucose-meter money. The conversion is honest and the exchange rate is fixed, but two things stay true of any conversion: no second transaction happened (the only measurement was the HbA1c), and a daily-average exchange rate is not the price you paid at any single shop.
The rate itself comes from research. In a 2008 study, investigators tracked continuous glucose in hundreds of people for several months and matched it to their HbA1c, producing the line the American Diabetes Association now uses: eAG in mg/dL equals 28.7 times your A1C minus 46.7. Every eAG you'll ever see is that one equation applied to one HbA1c.
| HbA1c | Estimated average glucose |
|---|---|
| 5.0% | 97 mg/dL |
| 5.7% | 117 mg/dL |
| 6.5% | 140 mg/dL |
| 7.0% | 154 mg/dL |
| 8.0% | 183 mg/dL |
Reading the eAG number
mg/dLBelow roughly 117 mg/dL corresponds to an HbA1c under 5.7%, the band the American Diabetes Association calls normal. The eAG can't say anything the A1C didn't already say.
Around 117 to 140 mg/dL mirrors the 5.7–6.4% prediabetes range. A warning with a long runway, read exactly as you'd read the A1C behind it.
An eAG near 140 mg/dL is the 6.5% mark where diabetes can be diagnosed, confirmed on a second test.
154 mg/dL is the 7% target many guidelines set for adults who already have diabetes. Individual targets shift with age and other conditions.
Why your eAG and your meter rarely agree
This is the confusion the number creates more than any other, and it's worth resolving plainly. People with a glucose meter compare the eAG to the average their device reports, find the eAG sitting higher, and assume one of them is broken. Neither is. They are counting different moments.
A meter captures the readings you decide to take. In practice that's mostly fasting and pre-meal checks during waking hours, the times of day glucose tends to be at its lowest. The eAG, through HbA1c, reflects glucose every minute for about three months, including the hours after meals when it climbs and the overnight stretch a meter almost never samples. An average built from morning fingersticks is sampling the calm water; the eAG includes the waves.
So a meter average that runs 15 or 20 mg/dL below the eAG usually means the meter is catching the good moments and missing the peaks, not that the lab made a mistake. The honest read is that a single glucose reading is one priced transaction, a meter average is a handful of them at chosen hours, and the eAG is the blended 24-hour rate. The HbA1c vs estimated average glucose comparison lays the two side by side.
The eAG inherits every flaw in the A1C
Because the eAG is pure arithmetic from HbA1c, it carries forward everything that can distort that number, with nothing of its own to correct it. The conversion can't know whether the A1C it was handed was trustworthy.
The situations that quietly bend HbA1c, and therefore the eAG with it:
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Iron deficiency
Red cells living on low ferritin survive longer and collect extra glucose coating, nudging HbA1c up without any real change in blood sugar. The eAG rises right along with it.
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Inherited hemoglobin variants
Sickle cell trait and similar variants can throw off the HbA1c assay itself. Whatever skew lands in the A1C is what the formula converts.
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A young red-cell population
Recent blood loss, hemolysis, or treatment that floods circulation with new cells pushes HbA1c down, and the eAG drops with it. This one runs the number low rather than high.
When a doctor decides the HbA1c can't be trusted, as the NIDDK advises in these situations, the eAG built from it is no more reliable, and the conversation moves to glucose-based tests. A fasting glucose measures the sugar present at the moment of the draw and makes no assumptions about red cells at all. Fructosamine reads a shorter, two-to-three-week window off blood proteins instead of hemoglobin. Because eAG is derived from A1C's three-month window, a shorter-window marker such as glycated albumin can reveal recent change that the average has not yet caught up to.
What the eAG is good for
For all that, the translation does a real job: it answers the question patients actually ask. "What is my sugar running, day to day?" is hard to picture from a percentage and easy to picture from a number a meter would show. An eAG near 154 mg/dL makes a 7% HbA1c concrete in a way the percent never quite does, which is the whole reason the American Diabetes Association publishes the conversion.
Treat it as a reading aid for the HbA1c, not a separate result. It belongs to the diabetes panel only as the A1C's translation, alongside fasting glucose and often insulin; the diabetes panel guide walks through how those pieces read together. And like the HbA1c it comes from, its real value is longitudinal: an eAG that has drifted from 130 to 160 over three readings says more than any single figure, because the direction tells you more than the number on any one day.
See your Estimated Average Glucose on one timeline.
BloodSight calibrates the reference range to your sex, age, and lab — and shows every value across every visit.
In your personal range
Normal ranges
| Group | Range | Unit |
|---|---|---|
| Adult | 70–126 | mg/dL |
Reference ranges may vary by laboratory and individual factors.
Estimated Average Glucose — Common Questions
Is estimated average glucose a real blood sugar test?
Why doesn't my eAG match my glucose meter average?
What is an eAG of 154?
What eAG matches a normal HbA1c?
Can iron deficiency or anemia throw off eAG?
Disclaimer
This content is for informational and educational purposes only. It is not intended as medical advice, diagnosis, or treatment recommendation. Reference ranges may vary by laboratory. Always discuss your results with a qualified healthcare professional.
Related Tests
One number that remembers everything: roughly three months of blood sugar, weighted toward recent weeks, immune to last-minute virtue. That long memory is also where the test can go wrong.
Glucose is a single photograph of your blood sugar, captured the instant the needle goes in. Whether you had eaten, the hour of day, even the stress of the draw can change what the picture shows.
Fasting glucose is the same blood sugar as any other glucose reading, measured under one strict rule: nothing but water for at least eight hours. That rule is what lets one morning's number be compared to the next.
Glucose tells you where your blood sugar landed. Fasting insulin tells you how hard your body worked to put it there, which is often the part the standard panel never shows.
Every insulin molecule the pancreas releases is paired with one C-peptide. Counting the stub tells you how much insulin your body makes, even when the insulin itself is gone in minutes or arrived from a syringe.
Hemoglobin is a concentration, not a headcount of your red cells. It reads high when you are dry, low when fluid floods in, and can sit perfectly normal while your iron quietly runs out.
Ferritin is your body's iron savings account. It's usually the first number to drop when iron runs low, often months before anything else looks abnormal.
Fructosamine is the glucose average that skips your red blood cells. It reflects the past two to three weeks, which makes it the test of choice when HbA1c can't be believed.
A two-to-three-week sugar marker reported as a fraction of your albumin, which means the protein it divides by can move the result on its own.