Health
A1C Calculator FAQ
Convert A1C to eAG, estimate A1C from readings, and check ADA risk bands.
FAQ
How is A1C converted to average glucose?+
It uses the ADAG study formula: eAG (mg/dL) = 28.7 x A1C - 46.7. For example, a 7% A1C converts to 154 mg/dL eAG. The reverse formula estimates A1C from an average glucose reading. The calculator supports both directions in the Convert tab.
Can estimated A1C from fingersticks replace a lab test?+
No. Home readings are estimates. Only a lab HbA1c test measures glycated hemoglobin directly and is the gold standard for diagnosis and monitoring. The estimated A1C from a glucose log is useful for tracking trends between lab visits but should not be used for treatment decisions without consulting your doctor.
What units does this support?+
It supports mg/dL (used in the US) and mmol/L (used in most other countries). Switch the unit toggle at the top of the calculator and all inputs, conversions, and risk band thresholds will update automatically.
What A1C level is considered normal?+
Below 5.7% is normal. 5.7% to 6.4% is prediabetes. 6.5% or higher is diabetes range. These thresholds come from the American Diabetes Association (ADA) clinical guidelines and are used internationally for diabetes screening and diagnosis.
How many glucose readings do I need for a good estimate?+
More readings produce a more reliable estimate. A minimum of 7-14 readings across different times of day (fasting, after meals, bedtime) over a 1-2 week period provides a reasonable snapshot. The calculator shows the reading count so you can assess the confidence level of the estimate.
What is the difference between eAG and A1C?+
A1C is a percentage that measures glycated hemoglobin in your blood over the past 2-3 months. eAG (estimated Average Glucose) converts that percentage into the same mg/dL or mmol/L units you see on your glucose meter, making it easier to understand how your daily readings relate to your A1C result.
Can I use this for gestational diabetes?+
The A1C conversion and glucose log features work for any glucose monitoring context. However, gestational diabetes has different diagnostic thresholds and target ranges. Consult your healthcare provider for pregnancy-specific glucose targets and A1C interpretation.