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This calculator converts between HbA1c and estimated average glucose (eAG) using the formula published by the ADAG (A1c-Derived Average Glucose) study: eAG (mg/dL) = 28.7 x A1C - 46.7. This calculator is for general reference and educational purposes only — it is not a medical diagnosis. Consult a doctor or qualified professional for actual diabetes management decisions.
How it works
Choose a direction (A1C to eAG, or eAG to A1C), then enter the known value. The tool applies the ADAG formula (or its algebraic reverse) and also reports the eAG in mmol/L.
- Enter conversion direction.
- Enter value (A1C % or eAG mg/dL, per direction above).
- Click Calculate to see your results.
Examples
A1C of 7%
eAG = 28.7 x 7 - 46.7 = 154.2 mg/dL (about 8.56 mmol/L).
Who should use it
- Translating a lab A1c result into the mg/dL or mmol/L units used by a home glucose meter.
- Patient education material relating A1c to everyday glucose numbers.
Industry applications
- Diabetes education and patient communication
- Primary care and endocrinology reference
Advantages
- Uses the same formula published and endorsed by the American Diabetes Association (ADA).
- Works in both directions (A1C to eAG and back).
Limitations
- eAG is a population-based estimate — individual correlation between A1c and average glucose can vary.
- Does not account for conditions (e.g. certain anemias) that can affect A1c accuracy.
Common mistakes to avoid
- Confusing eAG (an estimate over roughly 2-3 months) with a single point-in-time blood glucose reading.
- Applying the ADAG formula to A1c values from methods or populations not represented in the original study.
Best practices
- Use eAG alongside your lab-reported A1c to relate lab results to typical daily glucose meter readings.
Tips
- Discuss both your A1c and eAG with your doctor — they reflect the same underlying control, just in different units.