HbA1c Calculator
Convert between HbA1c percentage and estimated average blood glucose (eAG).
What is HbA1c?
HbA1c (glycated hemoglobin) measures the percentage of hemoglobin in your blood that has glucose attached to it. Because red blood cells live for about 2-3 months, HbA1c gives you a picture of your average blood sugar levels over the past 2-3 months.
Unlike a fasting blood glucose test that captures a single moment, HbA1c reveals long-term blood sugar control — making it the gold standard for diagnosing and monitoring diabetes.
HbA1c Ranges
Normal
Below 5.7%
Prediabetes
5.7% - 6.4%
Diabetes
6.5% or higher
The Formula
This calculator uses the widely accepted formula from the ADAG study:
This tool is for educational purposes only and does not replace professional medical advice. Always consult your healthcare provider about your test results.
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