Nevermind everybody. I just did some research on wheel diameter sizes and found the following... Posting this in case someone might find it useful. The number on the left of the "=" is the advertised wheel diameter. The number on the right of the "=" is the true diameter.
From largest to smallest...
27" = 630mm
29" = 622mm
700c = 622mm
650c = 571mm
26" = 559mm (Note: this is for most mountain bike tire. Other 26" tires such as cruiser tires, 1960s, 1970s bikes, etc are different)
I think this is pretty accurate. I have no idea how a 27" wheel is actually bigger in diameter than a 29" wheel. Oh well.