A1c 4.5%
A1c of 4.5%: what it means
An A1c of 4.5% is in the normal range, 1.2 points below where prediabetes starts. It maps to an average glucose of about 82 mg/dL. Values this low can also come from faster red blood cell turnover.
Average glucose from the ADAG formula, eAG = 28.7 × A1c − 46.7 (Nathan 2008). Categories from the ADA Standards of Care (ADA Standards 2026, sec. 2).
What an A1c of 4.5% means
- The ADA defines a normal A1c as below 5.7%. From 5.7% to 6.4% is prediabetes, and 6.5% or higher is diabetes. (ADA Standards 2026, sec. 2)
- The ADA criteria have no lower cut point: every A1c below 5.7% falls in the normal range. A low result is worth a second look mainly when it does not fit glucose readings, since the ADA recommends checking for interference when the two disagree substantially. (ADA Standards 2026, sec. 2)
- Faster red blood cell turnover, for example after blood loss or with hemolysis, usually lowers A1c, so a result can understate average glucose in those cases. (ADA Standards 2026, sec. 2)
- For people treated for diabetes, the ADA says health professionals should not aggressively aim for near-normal A1c levels in people who cannot reach them safely, because severe hypoglycemia is strongly linked with cardiovascular events and death. (ADA Standards 2026, sec. 6)
Questions to ask your doctor
- Given my risk factors, when should I be tested again?
- Would a fasting glucose or glucose tolerance test add anything for me?
- Could anything make my A1c read low, such as anemia, blood loss or a hemoglobin variant?
Read next: what the A1c test measures, A1c by age, the prediabetes A1c range, low A1c. Lab reports in mmol/mol? Use the HbA1c mmol/mol converter.
Nearby values
| A1c | mg/dL | mmol/L | Category |
|---|---|---|---|
| 4.0% | 68 | 3.8 | Normal |
| 4.1% | 71 | 3.9 | Normal |
| 4.2% | 74 | 4.1 | Normal |
| 4.3% | 77 | 4.3 | Normal |
| 4.4% | 80 | 4.4 | Normal |
| 4.5% | 82 | 4.6 | Normal |
| 4.6% | 85 | 4.7 | Normal |
| 4.7% | 88 | 4.9 | Normal |
| 4.8% | 91 | 5.1 | Normal |
| 4.9% | 94 | 5.2 | Normal |
| 5.0% | 97 | 5.4 | Normal |
All values from 4.0% to 14.0% are in the A1c chart. Planning a retest? See how fast A1c can change. Over 65? See A1c by age.
Try another number
Estimated average glucose (eAG) = 28.7 × A1c − 46.7, from the ADAG study. mmol/L = mg/dL ÷ 18.016. Real averages vary from person to person at the same A1c. This is a conversion, not a diagnosis.
Other key numbers
6.5 mmol/L
6.6 mmol/L
6.8 mmol/L
7.0 mmol/L
7.1 mmol/L
7.3 mmol/L
7.4 mmol/L
7.6 mmol/L
7.8 mmol/L
8.6 mmol/L
9.4 mmol/L
10.2 mmol/L
10.9 mmol/L
11.7 mmol/L
13.3 mmol/L
14.9 mmol/L
16.5 mmol/L
Sources
- Nathan DM, Kuenen J, Borg R, Zheng H, Schoenfeld D, Heine RJ; A1c-Derived Average Glucose (ADAG) Study Group. Translating the A1C assay into estimated average glucose values. Diabetes Care. 2008;31(8):1473-1478. doi.org/10.2337/dc08-0545
- American Diabetes Association Professional Practice Committee. 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes 2026. Diabetes Care. 2026;49(Suppl 1). doi.org/10.2337/dc26-S002
- American Diabetes Association Professional Practice Committee. 6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes 2026. Diabetes Care. 2026;49(Suppl 1). doi.org/10.2337/dc26-S006
Written and maintained by the controla1clevels.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-25. Spotted an error? See About.