A1c reflects average blood sugar over about three months. Converting it to glucose units makes it easier to compare with finger-stick readings.
How to use the A1c to Average Glucose Calculator
- Hemoglobin A1c
- Want to work backwards? Type a value into Estimated average glucose and Hemoglobin A1c is calculated for you.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Multiply A1c by 28.7 and subtract 46.7 for mg/dL; divide by 18 for mmol/L.
Example values
How the main result changes when Hemoglobin A1c changes and everything else stays at the example values above:
| Hemoglobin A1c (%) | Estimated average glucose (mg/dL) |
|---|---|
| 3.5 | 54 |
| 5.25 | 104 |
| 7 | 154 |
| 8.75 | 204 |
| 10.5 | 255 |
| 14 | 355 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
eAG (mg/dL) = 28.7 × A1c − 46.7Worked example
Inputs — Hemoglobin A1c: 7 %.
Results — Estimated average glucose = 154 mg/dL; A1c category = 7 %.
Key terms
- HbA1c
- Glycated haemoglobin, a marker of average glucose.
Frequently asked questions
What A1c indicates diabetes?
6.5% or higher on two tests, according to the American Diabetes Association.
Why might A1c not match my meter?
Anaemia, recent blood loss and some haemoglobin variants affect A1c.
What formula does the A1c to Average Glucose Calculator use?
eAG (mg/dL) = 28.7 × A1c − 46.7.
Can I work backwards from the result?
Yes. Type the result you want into Estimated average glucose and the calculator finds the matching hemoglobin a1c.