If you overstayed 30 days you’re going to have to pay a fine for those days and be ready to leave the country immediately.  you will then have to apply for a new visa at a Thai Consulate which will probably take you a few days or a week.  Be totally RESPECTFUL towards any of the authorities and don’t argue with them about anything they say. Just agree to do it. It wouldn’t hurt to dress a little more formally than wearing shorts and flip-flops, and for God’s sake bathe and wash your hair before you show up. 

@Kool ******

Yup

@Steve *******

The extension stamp they give you upon your 90 day reporting has the new 90 day date.

@Marty ********

And you can report up to 14 days early or up to 7 days beyond your scheduled date. It’s a grace period.

@Mark *****

Yup.

Nope. You can report 7 days after the 90 days and still be ok.

@Steve ******

Thanks much.

@Bob *********

Thanks, I’m covered then.

@John *********

Thanks again.