A1C of 6.1% is an average glucose of 128 mg/dL
Estimated average glucose at A1C 6.1%
128 mg/dL
- In mmol/L
- 7.1 mmol/L
- A1C entered
- 6.1%
- ADA range
- the range the ADA defines as prediabetes
The estimated average glucose behind an A1C of 6.1% is 128 mg/dL, or 7.1 mmol/L. That A1C would appear as approximately 43 mmol/mol on a report using IFCC units.
The ADA defines the band from 5.7% to 6.4% as prediabetes. That is a definition of a range rather than a diagnosis of a person: diagnosing requires a clinician, usually a repeat test, and your history read alongside it.
A1C 6.1% is in the upper half of the ADA prediabetes range and one of the most-searched values on the scale. Note that a UK or Australian report would show this as roughly 43 mmol/mol in IFCC units, which is the same measurement wearing different clothes.
One tenth higher, at 6.2%, the estimate reaches about 131 mg/dL — a difference of roughly 3 mg/dL. Set against the 0.5 percentage points a certified assay may vary by, that is a very small step indeed.
If you are going to take one thing from this page, take the comparison rather than the reading: a number in isolation is trivia, and the same number tracked over time is information.
Which glucose unit you see is a matter of geography: the United States and India generally report mg/dL, while the UK, Australia and Canada generally report mmol/L.
Anything that alters red blood cell turnover — anaemia, recent blood loss, a transfusion, pregnancy, chronic kidney disease, some haemoglobin variants — moves A1C independently of glucose, in either direction.
A steady day and a volatile day can average out to the same figure. If that distinction matters for you, it is continuous monitoring rather than a periodic average that shows it.
| A1C | eAG (mg/dL) | eAG (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 |
| 6.6% | 143 mg/dL | 7.9 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
What is an A1C of 6.1% in average blood sugar?
Where does 6.1% fall on the ADA scale?
What should I ask my clinician about 6.1%?
How precise is the 128 mg/dL figure?
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