What the A1C to blood sugar conversion shows
The A1C (or HbA1c) test reflects your average blood sugar over the past two to three months. This calculator converts an A1C percentage into an estimated average glucose in both mg/dL and mmol/L, so you can compare a lab A1C with the day-to-day readings from a home meter.
The formula
Estimated average glucose (mg/dL) = 28.7 x A1C - 46.7. Divide by 18 to get mmol/L.
Worked example
An A1C of 7% converts to an estimated average glucose of about 154 mg/dL, or 8.6 mmol/L.
Frequently asked questions
What does A1C measure?
Your average blood sugar over roughly the past two to three months, shown as a percentage. It smooths out the daily ups and downs.
What A1C is normal?
General reference points are below 5.7% normal, 5.7 to 6.4% prediabetes range, and 6.5% or above in the diabetes range. Your doctor interprets your result.
Is eAG the same as my meter reading?
It is the long-term average your A1C reflects, in the same units. Individual meter readings vary through the day around that average.
What A1C is considered normal?
Ranges vary and only your provider can interpret your result. This tool just converts A1C to average glucose; it does not diagnose.
Is this medical advice?
No. It is a standard conversion for general information. Always follow your healthcare provider's guidance.