A1C to Average Glucose Converter
HbA1c (glycated hemoglobin) reflects average blood glucose levels over the past 2–3 months. The American Diabetes Association formula converts A1C percentage to estimated average glucose (eAG): eAG (mg/dL) = 28.7 × A1C − 46.7. This bidirectional converter also reverses the calculation — enter an average glucose reading to estimate the corresponding A1C value.
Understanding your A1C alongside daily glucose readings gives a fuller picture of glycemic control. An A1C below 5.7% is considered normal, 5.7–6.4% indicates prediabetes, and 6.5% or above is diagnostic for diabetes. Always discuss your results with a qualified healthcare professional.
How it works
eAG (mg/dL) = 28.7 × A1C% − 46.7; eAG (mmol/L) = eAG (mg/dL) ÷ 18.0182. Reverse: A1C% = (eAG + 46.7) ÷ 28.7. Source: ADA ADAG study.
Use cases
- Converting a lab HbA1c result to an average blood sugar number you can relate to daily readings
- Estimating what A1C your continuous glucose monitor average implies
- Tracking glycemic progress between quarterly checkups
- Educating patients on the relationship between A1C and daily glucose values
- Comparing mg/dL and mmol/L glucose units used in different countries
Frequently asked questions
How does the A1C to average glucose conversion work?
The converter uses the American Diabetes Association formula eAG (mg/dL) = 28.7 × A1C − 46.7, derived from the ADAG study. Enter your HbA1c percentage and the tool returns your estimated average glucose in both mg/dL and mmol/L. The calculation also works in reverse, estimating the A1C that corresponds to a given average glucose reading.
What is a normal A1C level?
An A1C below 5.7% is generally considered normal, a value between 5.7% and 6.4% indicates prediabetes, and 6.5% or above is diagnostic for diabetes. These are standard reference ranges used by the American Diabetes Association. Always review your individual results with a qualified healthcare professional.
What does an A1C of 7 mean in average blood sugar?
Applying the formula, an A1C of 7% corresponds to an estimated average glucose of about 154 mg/dL (28.7 × 7 − 46.7), or roughly 8.6 mmol/L. This means your blood sugar averaged around that level over the past 2–3 months. It is an estimate, so individual daily readings will naturally vary above and below it.
Why is my A1C different from my glucose meter average?
A1C reflects a weighted average over the lifespan of your red blood cells (about 2–3 months), while a meter or CGM average only covers the readings you actually take. Timing of tests, glucose variability, and individual differences in red blood cell turnover can all cause the two numbers to diverge. The eAG formula gives an estimate, not an exact match for every person.
How do I convert average glucose from mg/dL to mmol/L?
Divide the mg/dL value by 18.0182 to get mmol/L, or multiply mmol/L by 18.0182 to get mg/dL. For example, 154 mg/dL is about 8.5 mmol/L. This converter shows both units automatically, which is helpful because mg/dL is common in the US and Brazil while mmol/L is used in many other countries.