"40k baht income.proven by a income letter from your embassy" 

via ubonjoe from different topic......

 

Can I get away with just the income affidavit from US Consulate of 40,000 baht or will they ask for bank statements and bank book ?

I keep my income in a joint account in a thai bank not one just in my name.

I make a combined 36,000 baht which is just short of that.

Lying on your declaration could have serious legal consequences with the US-Govt, and Thai-Govt - not recommended.  Maybe some of your reported income could come from cashing in part of your savings each year ( only ~48K Baht/yr would bring you up to 40K/mo)?

 

Sometimes, people are asked to show some proof of income.  A joint-account with  your wife, with foreign-transfers going in might help, since it is not being used for the "proof of 400K in the bank" option, which would need to be in your name only.  You might also have ATM withdrawals, so the Thai-joint account might not show all your incoming funds.  I have started trying to send more of my spending-money into my Thai account, and not using ATM-cards from foreign accounts, to simply any proof if requested.

19 minutes ago, tstcman said:

Can I get away with just the income affidavit from US Consulate of 40,000 baht or will they ask for bank statements and bank book ?

All immigration should want is the income affidavit.They can ask for proof income being received in Thailand, 

but I don't think they do in Chiang Mai.