Quick guide
How to use this calculator
- Use the labels and unit notes to enter the requested measurement, date, time, or observation exactly as recorded.
- Check the visible method, population, and unit basis before using the result; switch modes rather than converting values mentally.
- Read the calculation audit and limitations together. The result supports measurement or tracking and does not replace diagnosis, treatment, or urgent medical assessment.
Calculation method
How the a1c and estimated average glucose calculator works
eAG (mg/dL) = 28.7×A1C (%) − 46.7; inverse A1C = (eAG + 46.7) ÷ 28.7. eAG mmol/L uses the glucose unit conversion factor.
eAG is a regression estimate associated with A1C, not the same as an individual's directly observed glucose average or glucose management indicator.
Worked example
A1C and Estimated Average Glucose example
An A1C of 7% corresponds to an ADAG eAG of about 154 mg/dL or 8.6 mmol/L.
eAG (mg/dL) = 28.7×A1C (%) − 46.7; inverse A1C = (eAG + 46.7) ÷ 28.7. eAG mmol/L uses the glucose unit conversion factor.
Supported inputs
Precision and limits
Supported purpose
The ADAG study evaluated adults and the calculator is restricted to its published 5–12% A1C table range (approximately 97–298 mg/dL eAG). Individual prediction intervals are wide. Conditions affecting red-cell lifespan, hemoglobin, kidney function, pregnancy, transfusion, or assay reliability can weaken the relationship. This tool does not set an A1C target or recommend treatment.
Measurement quality
The output is only as reliable as the entered measurement, device, timing, units, and applicable reference population. Recheck unexpected values against the original record.
Clinical boundary
This calculator does not diagnose a condition, choose treatment, change medication, or determine that an urgent symptom is safe to monitor at home. Contact an appropriate health professional or local emergency service when the situation may be urgent.
Privacy
Entered health values and results stay in this browser tab. They are not placed in URLs, analytics, logs, local storage, session replay, or a cloud record by this calculator.
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