A1C to eAG Calculator
| A1C | eAG mg/dL | eAG mmol/L |
|---|---|---|
| 5% | 97 | 5.38 |
| 5.5% | 111 | 6.18 |
| 6% | 126 | 6.97 |
| 6.5% | 140 | 7.77 |
| 7% | 154 | 8.57 |
| 7.5% | 169 | 9.36 |
| 8% | 183 | 10.16 |
| 8.5% | 197 | 10.96 |
| 9% | 212 | 11.76 |
| 9.5% | 226 | 12.55 |
| 10% | 240 | 13.35 |
| 10.5% | 255 | 14.15 |
| 11% | 269 | 14.94 |
| 11.5% | 283 | 15.74 |
| 12% | 298 | 16.54 |
| 12.5% | 312 | 17.34 |
| 13% | 326 | 18.13 |
| 13.5% | 341 | 18.93 |
| 14% | 355 | 19.73 |
Your A1C and your average glucose are the same signal in two units. The ADAG study - the 507-person trial that gave the world the formula - fitted the line directly: estimated average glucose (mg/dL) = 28.7 x A1C - 46.7, with R-squared 0.84. Enter your latest A1C and this page converts it to the number your home meter speaks, in mg/dL or mmol/L - or run it backwards from your meter average to the A1C your lab should expect.
One caution before you convert: eAG is a three-month weighted average of your glucose, not a target and not a substitute for daily readings. NIDDK puts it plainly - the eAG number will not match your daily glucose readings because it is a long-term average rather than your blood glucose at a single time.
How to use
- Pick the direction: A1C percent to estimated average glucose, or your meter's 90-day average in mg/dL back to an A1C percent. The formula runs both ways.
- Enter the value and read the conversion - the table below carries the full 5.0% to 14.0% ladder at half-point steps, in both mg/dL and mmol/L for lab reports from outside the US.
- Sanity-check against your meter: if your readings never come close to the eAG, bring the discrepancy to your clinician - the estimate assumes your meter average over three months, not last week.
Frequently asked questions
What is eAG - estimated average glucose?
NIDDK: eAG is calculated from your A1C, and some laboratories report it alongside the A1C result. It converts the A1C percentage into the same milligrams-per-deciliter units your home glucose meter uses, which makes the three-month lab number feel like something you can compare to your day-to-day readings.
Why does eAG not match my meter readings?
Because it is an average over roughly three months, weighted toward the most recent weeks - while a meter reading is one moment. An eAG of 154 mg/dL is entirely consistent with mornings at 110 and evenings at 220. The range between your highest and lowest readings is information the A1C throws away.
How accurate is the 28.7 x A1C - 46.7 formula?
It is the best-fit line from the ADAG study (Nathan et al., Diabetes Care 2008): R-squared 0.84, P under 0.0001, and the study found the equation did not differ significantly across subgroups of age, sex, diabetes type, race or ethnicity, or smoking status. About 16% of the variation between people is still not explained by A1C alone, which is why the lab report is the one to act on.
How do I convert mmol/L to mg/dL for glucose?
Multiply mmol/L by 18 (or divide mg/dL by 18 to go the other way) - the same constant this page applies to eAG. Cholesterol and triglycerides use different constants; the lab-unit converter handles all three analytes side by side.
Does A1C show short-term glucose spikes?
Only partially. NIDDK: large changes over the past month will show up in the A1C, but sudden, temporary increases will not. A rough weekend of high readings moves the three-month average less than you would expect - the reverse is also why one clean week does not fix a high A1C.