I was just looking at the Planner Inserts, and noticed that a whole bunch of the Webster's Pages inserts for their planners are all saying that they are size A2, but are listed as measuring 6-3/4x4. This can't be correct. A2 paper (an international measurement), is 16.5 x 23.4 in.
Here is a link on understanding A- paper sizes.
Basically, A4 is comparable to an 8-1/2 x 11" paper. Anything A3-A1 is much bigger than that. Papers A5+ are much smaller.