Understanding HbA1c and Average Glucose
HbA1c, or glycated hemoglobin, is a blood test that reflects your average blood glucose levels over the past 2 to 3 months. It measures the percentage of hemoglobin proteins in your blood that are coated with sugar (glycated). The higher your blood sugar levels have been over time, the higher your HbA1c will be.
Why HbA1c Matters
HbA1c is a widely used marker for diagnosing and managing diabetes. Unlike daily fingerstick tests or continuous glucose monitors (CGMs) that show real-time glucose levels, HbA1c provides a long-term view of your blood sugar control. Most diabetes management plans include routine HbA1c checks every 3 to 6 months.
Estimated Average Glucose (eAG)
Many patients find it easier to understand blood sugar values in terms of units like mg/dL or mmol/L, rather than as a percentage. The Estimated Average Glucose (eAG) is a standardized way of converting HbA1c to more familiar glucose values.
This calculator uses formulas developed by the ADAG (A1c-Derived Average Glucose) study, which established a strong correlation between HbA1c and continuous glucose monitoring data.
Typical HbA1c to eAG Conversions
| HbA1c (%) | eAG (mg/dL) | eAG (mmol/L) |
|---|---|---|
| 6.0 | 126 | 7.0 |
| 7.0 | 154 | 8.6 |
| 8.0 | 183 | 10.2 |
| 9.0 | 212 | 11.8 |
| 10.0 | 240 | 13.3 |
Target HbA1c Levels
- Non-diabetic: Below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher
For most adults with diabetes, an HbA1c goal of less than 7% is recommended, though individual targets may vary. Always follow your healthcare provider's advice regarding your specific treatment goals.