A1c 5.5%
A1c of 5.5%: what it means
An A1c of 5.5% is in the normal range, 0.2 points below the 5.7% start of prediabetes. It maps to an average glucose of about 111 mg/dL.
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 5.5% 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)
- Repeat tests on the same sample vary a little. NIDDK gives the example that a result of 6.8% could read anywhere from 6.4% to 7.2% on a repeat test. (NIDDK)
- For people without prediabetes or diabetes after screening, the ADA says repeat screening at least every 3 years is reasonable, sooner with symptoms or a change in risk such as weight gain. (ADA Standards 2026, sec. 2)
- A1c and glucose tests do not always agree. NIDDK notes that a glucose test can show diabetes when an A1c does not, and the reverse. (NIDDK)
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. Lab reports in mmol/mol? Use the HbA1c mmol/mol converter.
Nearby values
| A1c | mg/dL | mmol/L | Category |
|---|---|---|---|
| 5.0% | 97 | 5.4 | Normal |
| 5.1% | 100 | 5.5 | Normal |
| 5.2% | 103 | 5.7 | Normal |
| 5.3% | 105 | 5.9 | Normal |
| 5.4% | 108 | 6.0 | Normal |
| 5.5% | 111 | 6.2 | Normal |
| 5.6% | 114 | 6.3 | Normal |
| 5.7% | 117 | 6.5 | Prediabetes |
| 5.8% | 120 | 6.6 | Prediabetes |
| 5.9% | 123 | 6.8 | Prediabetes |
| 6.0% | 126 | 7.0 | Prediabetes |
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
- National Institute of Diabetes and Digestive and Kidney Diseases (NIH). The A1C Test & Diabetes. www.niddk.nih.gov/health-information/diagnostic-tests/a1c-test
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: 2026-10-27. Spotted an error? See About.