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Glucose to A1C Calculator
Have an average glucose number and want to know the A1C it corresponds to? This calculator back-solves your A1C from an average blood glucose using the ADAG equation the same one labs use to report estimated average glucose (eAG) alongside A1C. The relationship is A1C = (average glucose + 46.7) / 28.7 when glucose is in mg/dL, so an average around 154 mg/dL works out to roughly 7.0%. Enter your average glucose in mg/dL or mmol/L to see the estimated A1C, the IFCC mmol/mol equivalent, and the ADA screening category. Remember this is an estimate: A1C measures glycated hemoglobin directly and can differ from any short-run average, so treat the result as a guide and confirm with a lab and a clinician. Free, private, and computed entirely in your browser.
A1C = (average glucose mg/dL + 46.7) / 28.7 (ADAG equation, reversed)
- Worked example: an average glucose of 154 mg/dL ≈ 7.0% A1C ≈ 53 mmol/mol
- ADA categories: normal <5.7%, prediabetes 5.7–6.4%, diabetes ≥6.5%
Frequently asked questions
How do I convert average glucose to A1C?
Use the reversed ADAG equation: A1C = (average glucose in mg/dL + 46.7) / 28.7. For example, 154 mg/dL gives about 7.0%. If your glucose is in mmol/L, multiply by 18.0156 to get mg/dL first. This is an estimate — a lab A1C measures glycated hemoglobin directly and can differ from a short-run average.
Is a glucose-to-A1C estimate the same as a lab test?
No. This converts an average glucose into the A1C it would roughly imply, but a laboratory A1C is a direct measurement over 2–3 months and is affected by red-cell lifespan. Conditions like anemia, hemoglobinopathies, pregnancy or kidney disease can make the two diverge. Use this as a planning estimate, not a diagnosis.