How to use it
Pick a direction
Choose A1C to glucose, or glucose to A1C, with the toggle at the top.
Enter your number
Type an A1C percentage, or an average glucose value in mg/dL.
Read the result
The estimate updates instantly with both unit values and the formula used.
About the A1C calculator
A1C reflects your average blood sugar over roughly two to three months. This tool uses the widely cited ADAG regression: eAG mg/dL = 28.7 × A1C − 46.7, and mmol/L = 1.59 × A1C − 2.59. Going the other way, A1C % = (mg/dL + 46.7) / 28.7. Results are rounded estimates for orientation only.
This is for general guidance, not medical advice. Lab methods and individual biology vary, so use your own test results and clinician for decisions about your health.
Questions
Is anything uploaded?
No for this tool. The conversion runs entirely in your browser and nothing is uploaded or stored.
Why does my reading differ from this estimate?
eAG is a population average from a regression formula. Your own glucose and A1C can differ from the estimate, which is why it is general guidance and not a diagnosis.
Is it free?
Yes. Simple Tools is designed as a free, fast utility suite.