Income earners 20 years and older can file as independents. These are the only categories that taxpayers fall into. In the United States couples have the choice to file separately or together with a joint return. If they decide to file jointly, their incomes are simply added together and divided by two to determine the taxable income under the unified tax table.
在這種情形下，如果張家先生一年賺廿四萬元，太太賺十二萬元，因先生收入的百分之廿已超過上限，因此只能扣除上限三萬六千元，太太依規定扣百分之卅，也是三萬六千元；李家剛好倒過來，先生賺十二萬、太太賺廿四萬，則兩人的扣除額分別是二萬四千元、七萬二千元。