A1C of 6% is an average glucose of 126 mg/dL
Estimated average glucose at A1C 6%
126 mg/dL
- In mmol/L
- 7 mmol/L
- A1C entered
- 6.0%
- ADA range
- the range the ADA defines as prediabetes
6.0% translates to an average glucose of about 126 mg/dL, which is 7 mmol/L in the units used across the UK, Australia and Canada. The IFCC equivalent of the A1C itself is close to 42 mmol/mol.
The 5.7% to 6.4% band is what the ADA defines as prediabetes, and this figure is in it. A clinician reads it next to your fasting glucose, your history and any symptoms, never on its own.
A1C 6.0% is a common reference point because it is a round number roughly equidistant from 5.7% and 6.5%. It converts to an estimated average glucose of 126 mg/dL, which is worth remembering for a separate reason: 126 mg/dL fasting is itself an ADA diagnostic threshold, on a different test measuring a different thing.
For comparison, 6.1% comes out at approximately 128 mg/dL, about 2 mg/dL higher. Differences of a tenth sit under the roughly 0.5-point measurement tolerance, so neighbouring values are often indistinguishable in practice.
The mmol/L figure on this page is the mg/dL figure divided by 18.0182, the molar factor for glucose, so the two are consistent with each other rather than each coming from a different equation.
How readily an individual glycates varies, which is one reason a continuous-monitor average and a laboratory A1C often disagree in the same person even when both are measured properly.
Time spent in range and time spent high or low are separate questions from the average, and they matter clinically in ways an average cannot capture.
The window is rolling rather than fixed, so an A1C taken today and one taken a month from now overlap substantially in the period they describe.
| A1C | eAG (mg/dL) | eAG (mmol/L) |
|---|---|---|
| 5.5% | 111 mg/dL | 6.2 mmol/L |
| 5.6% | 114 mg/dL | 6.3 mmol/L |
| 5.7% | 117 mg/dL | 6.5 mmol/L |
| 5.8% | 120 mg/dL | 6.7 mmol/L |
| 5.9% | 123 mg/dL | 6.8 mmol/L |
| 6.0% | 126 mg/dL | 7 mmol/L |
| 6.1% | 128 mg/dL | 7.1 mmol/L |
| 6.2% | 131 mg/dL | 7.3 mmol/L |
| 6.3% | 134 mg/dL | 7.4 mmol/L |
| 6.4% | 137 mg/dL | 7.6 mmol/L |
| 6.5% | 140 mg/dL | 7.8 mmol/L |
- Estimated average glucose (ADAG / Nathan) — eAG (mg/dL) = 28.7 x A1C - 46.7. Verified against Nathan et al., Diabetes Care 2008 (ADAG study) (A population regression: in the ADAG study, individuals at the same A1C had meaningfully different mean glucose. The A1C assay itself carries about +/- 0.5 percentage points under NGSP certification.)
Official sources
- Nathan DM et al., Translating the A1C Assay Into Estimated Average Glucose Values, Diabetes Care 2008 — The ADAG study that produced the eAG equation used on this page.
- American Diabetes Association — Standards of Care in Diabetes — Where the A1C ranges quoted here are defined.
- NGSP — A1C assay standardisation and certification criteria — Why two lab results half a point apart can mean nothing changed.
Frequently asked questions
If my A1C is 6.0%, what is my average glucose?
How does the ADA describe an A1C of 6.0%?
Can something other than glucose produce an A1C of 6.0%?
Does an A1C of 6.0% tell me about my glucose swings?
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