This HbA1c calculator converts an A1c percentage into estimated average glucose (eAG), the average blood sugar it reflects over about three months. Enter your A1c above.
Formula (ADAG study)
eAG (mg/dL) = 28.7 × A1c − 46.7
Example
A1c 7%: eAG = 28.7 × 7 − 46.7 = 154 mg/dL (about 8.6 mmol/L).
Reference ranges
Normal < 5.7% | Prediabetes 5.7-6.4% | Diabetes ≥ 6.5%
Only a clinician can diagnose or manage type 2 diabetes; these ranges are for general reference.
Important
This tool is for general educational purposes only and is not medical advice, diagnosis, or treatment. It does not replace evaluation by a qualified healthcare professional — consult one for any health concern. Last updated: August 2026.
Frequently Asked Questions
How do I convert A1c to average glucose?
Use eAG = 28.7 times A1c minus 46.7 for mg/dL. An A1c of 7% is about 154 mg/dL.
What A1c indicates diabetes?
An A1c of 6.5% or higher generally indicates diabetes, and 5.7-6.4% indicates prediabetes — confirmed by a clinician.
What does A1c measure?
The average blood glucose over roughly the previous two to three months, based on glycated hemoglobin.