With effective from 1st January 2017, there is a revision of Personal Income Tax Structure with the following details:
1) Expense allowance for taxable incomes have been revised from 40% of the assessable income but not exceeding THB60,000 to 50% of the assessable income but not exceeding THB100,000.
2) Personal allowance has been revised from THB30,000 to THB60,000
3) Spouse not working allowance has been revised from THB30,000 to THB60,000
4) Child allowance has been revised from THB15,000 for each child to THB30,000 for each child with the total number of children not exceed 3 persons
5) The amount of THB2,000 of educational expense for each child has been cancelled
You may find the below link from Revenue Department for your reference :
http://www.rd.go.th/publish/fileadmin/user_upload/kormor/newlaw/prb44.pdf
Please note that there is only Thailand version for the official Gazette.