I was trying to use the new formula that links A1c to average blood glucose and could not find an online calculator so I wrote one myself. It will also convert mmol/L to mg/dl and back again using the truly accurate 18.05 conversion factor.
The new ADAG formula yields different blood sugar equivalents than did the older DCCT formula most of us are familiar with. Becuase it was derived from CGMS observations, it is supposed to be more accurate.
Here’s the calculator: http://bloodsugar101.com/A1Ccalc.php