30 days from the date the 60 day visa expires. I assume its the later, but I wanted to make sure before I visited Chiang Mai immigration. I couldn't find this specific information on this forum. Thanks.

Application for extension of tourist visa

Required documents

TM. 7 (application must be made in person)

Passport copy

Passport picture 4x6 cm

Application fee 1,900.- Baht

Documents required for special cases:

Illness:

Hospital certificate stating the doctor's examination with the followimg details:

Kind of illness,

Whether/How the illness prohibits traveling.

Visa Stamp

Foreigners applying for the first time for an extension of stay are given a 30 day extension from the date of expiry of the original admission, except for citizens of Sri Lanka, India, Pakistan, Iran, Bangladesh, Nepal, Nigeria, Togo, and Uganda, whose application for extension of stay will not be approved and the applicants are ordered to leave the kingdom within seven days.

If a foreigner wishes to apply for a second extension after being admitted to the Kingdom for 90 days,

the applicant is asked to report to the immigration office again in 15-30 days from the date of application, according to case if he produces evidence of necessity of extension,

the applicant is asked to report to the immigration office again in 15 days from the date of application if the applicant does not produce evidence or documentation. During the period of consideration the applicant is allowed to remain in the Kingdom.

Note

For more information, please call 0-2213-2556

Source: Immigration Website

Another option:

Go to any travel agent in Chiangmai and book a seat for the visa run to Mae Sai...... 600 Baht.

Cross into Myanmar, spend 250 Baht for your entry/exit stamps, return to Thailand and receive another 30 days for free.

No xeroxs, no pictures required just 850 Baht.