An A1C converter uses the American Diabetes Association formula eAG (mg/dL) = 28.7 × A1C − 46.7 to translate your A1C percentage into an estimated average glucose. For example, an A1C of 6.0% equals 126 mg/dL (7.0 mmol/L). The full chart below covers every A1C from 4.0% to 14.0% in both mg/dL and mmol/L, plus the IFCC (mmol/mol) conversion used in Europe and Australia.
The A1C Conversion Formulas
- A1C (%) to eAG (mg/dL): eAG = 28.7 × A1C − 46.7
- mg/dL to mmol/L: divide by 18 (or multiply by 0.0555)
- A1C (%) to IFCC (mmol/mol): IFCC = (A1C − 2.15) × 10.929
Full A1C Conversion Chart
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) | IFCC (mmol/mol) |
|---|---|---|---|
| 4.0 | 68 | 3.8 | 20 |
| 4.5 | 82 | 4.6 | 26 |
| 5.0 | 97 | 5.4 | 31 |
| 5.5 | 111 | 6.2 | 37 |
| 5.7 | 117 | 6.5 | 39 |
| 6.0 | 126 | 7.0 | 42 |
| 6.5 | 140 | 7.8 | 48 |
| 7.0 | 154 | 8.6 | 53 |
| 7.5 | 169 | 9.4 | 58 |
| 8.0 | 183 | 10.2 | 64 |
| 8.5 | 197 | 10.9 | 69 |
| 9.0 | 212 | 11.8 | 75 |
| 9.5 | 226 | 12.5 | 80 |
| 10.0 | 240 | 13.3 | 86 |
| 11.0 | 269 | 14.9 | 97 |
| 12.0 | 298 | 16.5 | 108 |
| 13.0 | 326 | 18.1 | 119 |
| 14.0 | 355 | 19.7 | 130 |
How to Use the A1C Converter
Pick the row that matches your A1C. The eAG in mg/dL is what your average blood glucose has been over the past 2 to 3 months, on the scale U.S. fingerstick meters use. The mmol/L column is the same number on the scale used in Canada, the UK, and Australia. The IFCC column is the alternate A1C unit used in European lab reports.
Example: If your lab reports an A1C of 6.5 percent, your estimated average glucose is 140 mg/dL (7.8 mmol/L), and your IFCC A1C is 48 mmol/mol. This is the diabetes diagnostic cutoff. For context on where this sits, see our A1C levels guide.
NGSP vs. IFCC: Why Two Units?
The NGSP (National Glycohemoglobin Standardization Program) unit (%) is used in the U.S. The IFCC (International Federation of Clinical Chemistry) unit (mmol/mol) is used in most of Europe. Both measure the same thing; the IFCC method is more precise and less affected by hemoglobin variants.
The historical reason for two units is the DCCT legacy. The landmark 1993 Diabetes Control and Complications Trial reported A1C as a percentage using a specific HPLC method, and every clinical target (6.5%, 7.0%, 8.0%) in the U.S. guidelines traces back to that study. NGSP-certified labs are calibrated to match the DCCT reference, so U.S. percentages remain comparable to 30 years of research. The IFCC developed a newer reference method in 2001 that measures the exact molar amount of glycated hemoglobin per total hemoglobin, reported in mmol/mol. It is metrologically cleaner but produces unfamiliar numbers (a “good” 6.5% becomes 48 mmol/mol), which is why the U.S. has not adopted it.
Why Different Countries Report Different Units
Reporting conventions reflect each country’s regulatory path:
- United States: NGSP only (percent). FDA and CMS reporting is tied to DCCT-aligned percentages.
- United Kingdom: IFCC only (mmol/mol) since June 2011. The NHS made a clean switch to avoid confusion.
- Canada, Australia, New Zealand: Dual reporting, with IFCC mmol/mol listed first and NGSP percent in parentheses.
- Most of continental Europe: IFCC mmol/mol as primary, often with percent shown alongside.
- Japan: Used a separate JDS standard until 2012, then aligned with NGSP. Older Japanese studies report values roughly 0.4 points lower than NGSP.
For glucose, the split is similar: the U.S. uses mg/dL while most of the world uses mmol/L. If you travel with a glucose meter, check that the unit matches what your doctor expects to see.
Worked Conversion Examples
Here are three realistic scenarios:
- U.S. lab report of A1C 5.9%: eAG = (28.7 × 5.9) − 46.7 = 169.3 − 46.7 = 122.6 mg/dL, or 122.6 / 18 = 6.8 mmol/L. IFCC = (5.9 − 2.15) × 10.929 = 41 mmol/mol.
- UK lab report of A1C 53 mmol/mol: To convert back to percent, NGSP = (IFCC / 10.929) + 2.15 = (53 / 10.929) + 2.15 = 4.85 + 2.15 = 7.0%. eAG = 154 mg/dL (8.6 mmol/L).
- Canadian report of A1C 6.5% with eAG 7.8 mmol/L: Convert mmol/L to mg/dL by multiplying by 18: 7.8 × 18 = 140 mg/dL. Confirms the diabetes diagnostic threshold.
Keep in mind the formula rounds slightly; clinical lab reports use the same equation but may display one extra decimal place.
When the Converter Is Off
The formula is based on population averages. Your personal conversion can differ if you have:
- Anemia or recent blood loss
- Hemoglobin variants (sickle cell trait, HbC, HbE)
- Chronic kidney disease
- Unusually fast or slow red blood cell turnover
If your CGM-reported average and your A1C-derived eAG differ by more than 20 mg/dL, ask your doctor about a fructosamine test.
A1C to Finger-Stick Reference
Your daily finger-stick readings should average close to the eAG. That means fasting readings are often a little below the average (for example, 120 mg/dL at an eAG of 140), while post-meal peaks are higher (for example, 160 to 180). A1C smooths all of this together.
Related Concepts
If you want to tie these numbers to what to eat to move them, read our diet and nutrition guide.
The Bottom Line
Convert A1C to average glucose with eAG = 28.7 × A1C − 46.7. Use the chart above for quick lookup in mg/dL, mmol/L, or IFCC mmol/mol. Remember the eAG is a population average, not a personal guarantee: your actual CGM or meter readings may differ by 10 to 30 mg/dL. Use the converter to translate lab results, not to replace daily glucose monitoring.
