How often can I take the GMAT?

[orestom]

I understand that I can take the GMAT once a month. Does that mean once every 30 days or once every calendar month? Thank you!

[StaceyKoprince]

It means once every 31 days, actually. So you can't take it on the last day of one month and then the first day of the next month (you used to be able to do this, but they changed it to "once every 31 days" a few years ago).