A1c 15.0%
A1c of 15.0%: what it means
An A1c of 15.0% means blood glucose has averaged about 384 mg/dL over the past few months.
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 15.0% means
- The ADA Standards of Care say early insulin should be considered when A1c is above 10%, when blood glucose is 300 mg/dL or higher, or when there are symptoms of high blood sugar or signs of catabolism such as unplanned weight loss. (ADA Standards 2026, sec. 9)
- The ADA Standards of Care describe an A1c goal below 7% as appropriate for many nonpregnant adults with diabetes, as long as it can be reached without significant hypoglycemia (low blood sugar). (ADA Standards 2026, sec. 6)
- Large changes in blood glucose over the past month show up in the A1c, but short spikes and dips do not. The most recent 30 days count more than earlier months. (NIDDK)
- People with diabetes are generally advised to have an A1c test at least twice a year, and more often when they are not meeting their goal. (NIDDK)
Compared with an A1c of 7.0% (154 mg/dL), an A1c of 15.0% means average glucose has been about 230 mg/dL higher.
Is an A1c of 15.0% good for a diabetic?
It depends on the goal set with your doctor. The ADA describes an A1c below 7% as an appropriate goal for many nonpregnant adults with diabetes, if it is reached without significant low blood sugar, and a less strict goal such as below 8% for some people, for example those with a history of severe low blood sugar, limited life expectancy or advanced complications. An A1c of 15.0% is above both the common 7% goal and the less strict 8% goal. Only your own care team can say which goal fits you. (ADA Standards 2026, sec. 6)
Questions to ask your doctor
- What A1c goal is right for me, and why?
- How often should my A1c be checked?
- Does my current treatment plan need to change?
- What blood sugar readings should I watch for at home, and when should I call you?
Read next: A1c goals in diabetes, A1c high but glucose normal. Lab reports in mmol/mol? Use the HbA1c mmol/mol converter.
Nearby values
| A1c | mg/dL | mmol/L | Category |
|---|---|---|---|
| 14.5% | 369 | 20.5 | Diabetes |
| 14.6% | 372 | 20.7 | Diabetes |
| 14.7% | 375 | 20.8 | Diabetes |
| 14.8% | 378 | 21.0 | Diabetes |
| 14.9% | 381 | 21.1 | Diabetes |
| 15.0% | 384 | 21.3 | Diabetes |
| 15.1% | 387 | 21.5 | Diabetes |
| 15.2% | 390 | 21.6 | Diabetes |
| 15.3% | 392 | 21.8 | Diabetes |
| 15.4% | 395 | 21.9 | Diabetes |
| 15.5% | 398 | 22.1 | Diabetes |
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. 9. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes 2026. Diabetes Care. 2026;49(Suppl 1). doi.org/10.2337/dc26-S009
- 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
- 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: 2026-11-01. Spotted an error? See About.