How is the duration of a Thai visa extension calculated: from the application date or expiration date?

@Jenna *****

someone else just posted their extention experience. He's also an American. Search recent posts, it should help you with what you need to provide. Good luck.

and what reason are you getting an extension for?

There are reports that the 60 day unable to travel extensions are counted from the date you apply (although I have no actual proof of this because no one has gone back and got the under consideration stamp changed to an extension yet)

As a general rule all extensions start the date your current stamp expires.