There are two formulas that I have seen used.

The usual formula to estimate the relationship between A1c and mean plasma glucose was derived from the DCCT study.

That formula is:

** Mean Blood Glucose = (A1c * 35.6) - 77.3 **

There is another, less cited formula that works better, at least for me. It is called "The Nathan Formula" it is:

**Mean Plasma Glucose = (A1c * 33.3) -86 ** This formula yields a mean plasma glucose which comes much closer to what my meter's 30 day average has looked like.

There are also a number of different online calculators that you can find by googling.

Cora