A1C Calculator
Estimate your A1C from average blood glucose, or find the average glucose that corresponds to any A1C level. Based on the ADA ADAG study formula.
Note: This is an estimate based on the ADAG formula. Only a lab HbA1c test gives a true result.
A1C to Average Glucose Reference Table
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) | IFCC (mmol/mol) | Category |
|---|---|---|---|---|
| 4.0% | 68 | 3.8 | 20 | Normal |
| 4.5% | 82 | 4.6 | 26 | Normal |
| 5.0% | 97 | 5.4 | 31 | Normal |
| 5.5% | 111 | 6.2 | 37 | Normal |
| 6.0% | 125 | 7.0 | 42 | Prediabetes |
| 6.5% | 140 | 7.8 | 48 | Diabetes — well-controlled (ADA target) |
| 7.0% | 154 | 8.6 | 53 | Diabetes |
| 7.5% | 169 | 9.4 | 58 | Diabetes |
| 8.0% | 183 | 10.2 | 64 | Diabetes |
| 8.5% | 197 | 11.0 | 69 | Diabetes |
| 9.0% | 212 | 11.8 | 75 | Diabetes |
| 9.5% | 226 | 12.5 | 80 | Diabetes |
| 10.0% | 240 | 13.3 | 86 | Diabetes |
| 10.5% | 255 | 14.1 | 91 | Diabetes |
| 11.0% | 269 | 14.9 | 97 | Diabetes |
| 11.5% | 283 | 15.7 | 102 | Diabetes |
| 12.0% | 298 | 16.5 | 108 | Diabetes |
| 12.5% | 312 | 17.3 | 113 | Diabetes |
| 13.0% | 326 | 18.1 | 119 | Diabetes |
| 13.5% | 341 | 18.9 | 124 | Diabetes |
| 14.0% | 355 | 19.7 | 130 | Diabetes |
Source: American Diabetes Association (ADA), ADAG study. IFCC values from the NGSP/IFCC master equation.
Glucoly – Blood Sugar Tracker
Glucoly tracks your A1C automatically
Log your blood sugar readings and Glucoly estimates your A1C in real time — no manual calculation. See how your A1C changes week over week and get trends before your next doctor visit.
What Is A1C?
A1C (glycated hemoglobin) reflects your average blood sugar over the past 2–3 months. Unlike a single glucose reading, it gives a long-term picture of blood sugar control. It is measured as a percentage of hemoglobin with attached glucose molecules.
How Is A1C Estimated from Average Glucose?
This calculator uses the ADAG (A1C-Derived Average Glucose) formula developed by the ADA: eA1C = (average glucose in mg/dL + 46.7) ÷ 28.7. This is an estimate — only a certified laboratory test gives your true A1C.
What Is a Good A1C?
For most adults with diabetes, an A1C below 7% is the ADA target. Below 5.7% is normal; 5.7–6.4% indicates prediabetes; 6.5% or above on two tests indicates diabetes. Individual targets vary — always discuss with your doctor.
Sources
- American Diabetes Association. Understanding A1c. Available at: https://diabetes.org/diabetes/a1c Accessed May 11, 2023.
- Nathan DM, Kuenen J, Borg R, Zheng H, Schoenfeld D, Heine RJ. Translating the A1C assay into estimated average glucose values. Diabetes Care. 2008;31(8):1473-1478. Available at http://care.diabetesjournals.org/content/31/8/1473.full.pdf
- American Diabetes Association. A1C and eAG. Available at: https://diabetes.org/living-with-diabetes/treatment-care/checking-your-blood-sugar
- Tylee TS, Trence DL. Glycemic variability: looking beyond the A1C. Diabetes Spectrum. 2012;24(3):149-153.