A1C Calculator.
Convert HbA1c to estimated average glucose (eAG) and back using the ADA formula. For educational use only — not medical advice.
6.5% or higher — may indicate diabetes range
Educational tool only. Not medical advice. Discuss lab results and targets with your healthcare provider.
What Is an A1C Calculator?
A1C (HbA1c) reflects average blood glucose over roughly the past 2–3 months. This free A1C calculator uses the American Diabetes Association (ADA) formula to estimate average glucose from your A1C percentage — or the reverse.
A1C to eAG Formula
To go the other way: A1C = (eAG + 46.7) ÷ 28.7. Convert mg/dL to mmol/L by dividing by 18.015.
Frequently Asked Questions (FAQs)
How do you convert A1C to average blood sugar?
Using the ADA formula: eAG (mg/dL) = 28.7 × A1C − 46.7. For mmol/L, divide the mg/dL result by 18.015.
What is a normal A1C level?
Generally, an A1C below 5.7% is considered within the normal range. 5.7%–6.4% may indicate prediabetes, and 6.5%+ may indicate diabetes. Always confirm with a healthcare professional.
Is this A1C calculator medical advice?
No. This tool is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.