This is very neat!
If you enter your A1c it will calculate your estimated Average Glucose (eAG) in either mg/dl or mmol/l units
It will also do the reverse and calculate what your A1c should be if you enter your estimated Average Glucose (eAG) from your meter, again in either mg/dl or mmol/l units.
It's really fun if you want to check out a few "what-if" scenarios, like what would my A1c be if I can lower my average blood sugar by say 20 points.
Here it is: