A1C to Average Blood Sugar (eAG) Calculator
Estimate your average blood glucose (eAG) from an A1C percentage, or estimate A1C from an average glucose reading, using the ADAG study formula adopted by the American Diabetes Association.
A1C to estimated average glucose (eAG) chart
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) |
|---|---|---|
| 5% | 96.8 | 5.372345739 |
| 5.5% | 111.15 | 6.168762695 |
| 6% | 125.5 | 6.965179652 |
| 6.5% | 139.85 | 7.761596608 |
| 7% | 154.2 | 8.558013564 |
| 7.5% | 168.55 | 9.35443052 |
| 8% | 182.9 | 10.15084748 |
| 9% | 211.6 | 11.74368139 |
| 10% | 240.3 | 13.3365153 |
| 11% | 269 | 14.92934921 |
| 12% | 297.7 | 16.52218313 |
eAG = 28.7 × A1C − 46.7 (mg/dL), based on the ADAG study (Nathan et al., 2008) used by the American Diabetes Association. Individual results can vary from this population-average estimate.
What Is eAG, and How Is It Different From a Glucose Reading?
A1C is reported as a percentage, which makes it hard to compare directly with the day-to-day mg/dL or mmol/L numbers from a glucose meter or continuous glucose monitor. eAG (estimated Average Glucose) solves that by converting A1C into the same units, so a lab report or an app can show “your A1C of 7% is about the same as an average glucose of 154 mg/dL” alongside the percentage. The relationship between A1C and eAG was established by the ADAG (A1C-Derived Average Glucose) study (Nathan et al., Diabetes Care, 2008), which tracked glucose readings alongside A1C in a large group of participants and fit a straight line between the two.
The A1C to eAG Formula
Example: an A1C of 7% → (28.7 × 7) − 46.7 = 154.2 mg/dL (about 8.56 mmol/L).
eAG to A1C (the reverse direction)
Example: an eAG of 154.2 mg/dL → (154.2 + 46.7) ÷ 28.7 = 7.0%.
To express eAG in mmol/L instead of mg/dL, divide the mg/dL result by 18.0182 (the same glucose factor used to convert mmol/L lab values to mg/dL).
A1C to eAG Conversion Chart
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) |
|---|---|---|
| 5.0 | 96.8 | 5.37 |
| 5.5 | 111.15 | 6.17 |
| 6.0 | 125.5 | 6.97 |
| 6.5 | 139.85 | 7.76 |
| 7.0 | 154.2 | 8.56 |
| 7.5 | 168.55 | 9.35 |
| 8.0 | 182.9 | 10.15 |
| 9.0 | 211.6 | 11.74 |
| 10.0 | 240.3 | 13.34 |
| 11.0 | 269.0 | 14.93 |
| 12.0 | 297.7 | 16.52 |
Use the calculator above for any A1C or eAG value not shown here.
Why eAG and a Single Glucose Reading Aren’t the Same Thing
It’s easy to look at an eAG of, say, 154 mg/dL and compare it to a single glucose-meter reading – but the two measure different things. A1C (and therefore eAG) reflects an average blood glucose level over roughly the past 2-3 months, weighted toward more recent weeks, because it’s based on how much glucose has attached to haemoglobin over the ~3-month lifespan of a red blood cell.
A single fingerstick or CGM reading, by contrast, is a snapshot of that exact moment, and will naturally swing above and below the eAG depending on meals, activity, stress and time of day. Someone with wide swings between very high and very low readings can have the same average – and the same eAG – as someone with steady, moderate levels, even though the two situations carry different risks.
What is the formula to convert A1C to eAG?
eAG (mg/dL) = 28.7 × A1C(%) − 46.7. For example, an A1C of 7% gives (28.7 × 7) − 46.7 = 154.2 mg/dL, or about 8.56 mmol/L.
How do I convert eAG back to an estimated A1C?
A1C(%) = (eAG in mg/dL + 46.7) ÷ 28.7. For example, an eAG of 154.2 mg/dL gives (154.2 + 46.7) ÷ 28.7 = 7.0%.
Where does the A1C to eAG formula come from?
It comes from the ADAG (A1C-Derived Average Glucose) study (Nathan et al., Diabetes Care, 2008), which compared A1C results with actual average glucose readings in a large group of participants and is the formula the American Diabetes Association uses to report eAG alongside A1C.
Is eAG the same as a single glucose reading?
No. eAG reflects roughly the last 2-3 months of average glucose, based on how A1C builds up on haemoglobin over a red blood cell’s lifespan, while a glucose-meter or CGM reading is a snapshot of one moment. The two numbers measure different things and won’t usually match exactly.
What does an A1C of 7% mean in average blood sugar?
Using the ADAG formula, an A1C of 7% corresponds to an estimated average glucose (eAG) of about 154.2 mg/dL, or roughly 8.56 mmol/L, over the preceding 2-3 months.
Can conditions other than blood sugar affect A1C?
Yes. Certain anaemias, haemoglobin variants, pregnancy, and kidney or liver disease can all push A1C higher or lower than a person’s true average glucose, independent of the ADAG formula. If this applies to you, your doctor may rely more on direct glucose monitoring than on A1C alone.
