An A1C of 6.0% corresponds to an estimated average glucose (eAG) of about 126 mg/dL, while an A1C of 7.0% equals roughly 154 mg/dL. The chart below provides a complete conversion from A1C 4.0% through 14.0%, helping you understand exactly what your A1C number means in terms of day-to-day blood sugar levels.
Both A1C and glucose tests play important roles in screening for prediabetes and diabetes. Understanding how to translate between them gives you a clearer picture of your metabolic health.
Complete A1C to Estimated Average Glucose Conversion Chart
The following chart converts A1C percentages to estimated average glucose in both mg/dL (used in the United States) and mmol/L (used in most other countries). Values are calculated using the ADAG formula.
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) | Classification |
|---|---|---|---|
| 4.0% | 68 | 3.8 | Normal |
| 4.5% | 82 | 4.6 | Normal |
| 5.0% | 97 | 5.4 | Normal |
| 5.5% | 111 | 6.2 | Normal |
| 5.7% | 117 | 6.5 | Prediabetes |
| 6.0% | 126 | 7.0 | Prediabetes |
| 6.4% | 137 | 7.6 | Prediabetes |
| 6.5% | 140 | 7.8 | Diabetes |
| 7.0% | 154 | 8.6 | Diabetes |
| 7.5% | 169 | 9.4 | Diabetes |
| 8.0% | 183 | 10.2 | Diabetes |
| 8.5% | 197 | 10.9 | Diabetes |
| 9.0% | 212 | 11.8 | Diabetes |
| 9.5% | 226 | 12.5 | Diabetes |
| 10.0% | 240 | 13.3 | Diabetes |
| 10.5% | 255 | 14.1 | Diabetes |
| 11.0% | 269 | 14.9 | Diabetes |
| 11.5% | 283 | 15.7 | Diabetes |
| 12.0% | 298 | 16.5 | Diabetes |
| 12.5% | 312 | 17.3 | Diabetes |
| 13.0% | 326 | 18.1 | Diabetes |
| 13.5% | 341 | 18.9 | Diabetes |
| 14.0% | 355 | 19.7 | Diabetes |
The ADAG Formula Explained
The conversion between A1C and estimated average glucose is based on the A1C-Derived Average Glucose (ADAG) study, a landmark international research project published in Diabetes Care in 2008. The study followed 507 participants and used continuous glucose monitoring to establish a reliable mathematical relationship between A1C and average glucose.
The formula is:
eAG (mg/dL) = (28.7 x A1C) – 46.7
To convert to mmol/L, divide the mg/dL result by 18:
eAG (mmol/L) = eAG (mg/dL) / 18
For example, if your A1C is 6.0%:
- eAG = (28.7 x 6.0) – 46.7 = 172.2 – 46.7 = 125.5 mg/dL (approximately 126 mg/dL)
- In mmol/L: 125.5 / 18 = 7.0 mmol/L
Keep in mind that eAG is an estimate. Your actual average glucose may differ by plus or minus 15-20 mg/dL due to individual variation in how glucose binds to hemoglobin.
When to Use A1C vs. Glucose Testing
A1C and glucose tests answer different questions. Understanding when each is most useful helps you and your doctor choose the right tool for the right situation.
| Scenario | Best Test | Why |
|---|---|---|
| Routine screening for prediabetes | A1C | No fasting required; reflects long-term trends |
| Confirming a new diabetes diagnosis | A1C + FPG or OGTT | Two different tests increase confidence in diagnosis |
| Monitoring diabetes management | A1C (every 3-6 months) | Shows whether treatment is maintaining target blood sugar |
| Detecting daily blood sugar patterns | Fingerstick glucose or CGM | Captures highs and lows throughout the day |
| Patient has hemoglobin variant or anemia | FPG or OGTT | A1C may be inaccurate due to altered red blood cell lifespan |
| Diagnosing gestational diabetes | OGTT | Preferred test during pregnancy; A1C may be unreliable |
Why Your A1C and Meter Readings May Not Match
If you test your blood sugar at home with a glucometer, you may notice that your daily readings don’t seem to match your A1C result. This is normal, and there are several reasons for the discrepancy:
- Timing of tests: You might test primarily when fasting or before meals, missing the post-meal spikes that raise your average.
- Overnight highs: Blood sugar can rise overnight (the “dawn phenomenon“) without you being aware of it.
- Glucose variability: If your blood sugar swings widely between highs and lows, the average (reflected in A1C) may not match any single reading.
- Individual biology: Some people glycate hemoglobin faster or slower than average, which means the standard formula may not perfectly predict their eAG.
If you notice a persistent mismatch between your A1C and home glucose readings, discuss it with your doctor. A continuous glucose monitor (CGM) can help reveal patterns you may be missing with spot checks. For more on understanding your A1C levels, see our detailed guide.
The Bottom Line
The A1C to glucose conversion chart is a practical reference tool that helps you understand what your A1C percentage means in everyday blood sugar terms. Using the ADAG formula — eAG (mg/dL) = (28.7 x A1C) – 46.7 — you can translate any A1C value into an estimated average glucose. Remember that A1C and glucose tests serve complementary purposes: A1C captures the long-term picture, while glucose tests show what’s happening right now. Talk to your doctor about which tests are most appropriate for your health situation and how to interpret your results in context.
For authoritative reference, consult the American Diabetes Association A1C diagnostic standards.
