With Chiang Mai Immigration (Near Airport) when applying for a 30 day extension of your 60 day entry stamp ...it is taken from when your stamp runs out or from day you apply? ....I always thought is was from when stamp runs out ..first time I do this ...have had tourist , retirement visas etc but never doe a stamp in ext.extension
TLDR : Answer Summary
When applying for a 30-day extension of a 60-day entry stamp at Chiang Mai Immigration, the extension is added to the end of your current stamp, not starting from the day you apply. This means you do not lose any days of the tourism extension by applying early, and you can request the extension up to 45 days in advance.