20,000 baht is the standard requirement for a single entry tourist visa. But you need to check the website of the embassy you are applying through to see what their specific requirement is. Many embassies set a higher amount in the native currency so they don't have to constantly adjust it when the exchange rate fluctuates up and down. For example here, is the requirement from the Thai embassy in Washington DC: Recent savings or checking bank statements for the last three months showing an ending balance of at least $ 700 for each month per person or $2,000 per family, with the applicant's name and date. If submitting a family bank statement (joint account), proof of relationship (e.g., birth certificate, marriage certificate) must be provided That's over 22,000 baht at today's exchange rate, but it makes it much easier for the embassy.
