How much income tax???

Firstly you don't need to post the same question in 3 different forums.

The link has been provided to you previously : http://www.rd.go.th/publish/6045.0.html

You have all the progressive tax rate in chapter 3 to do your calculation. You put all of this in an excel spreadsheet and you will arrive to basic 225,000 THB tax for single without any deductions !!

After the basic calculation for single tax payer can be reduced if you are married, have kid, etc....( all explained in chapter 2.2 allowances and deductions ), that means your total income 1,440,000 THB will be reduced this will affect the last progressive rate of 25% only as it is between 1M and 2M

You can find some app for iphone or android to calculate Thai income Tax

Thanks so much! Appreciate it.