The Marriage Penalty
Special Report No. 77
Many elements of the tax code vary with marital status, including the amount of the standard deduction, the earned income tax credit, and the tax rate schedule. All of these differences can cause a married couple to have different tax liability that two similarly situated single people.
A married couple filing jointly incurs a “marriage penalty” if their tax bill is higher than the combined tax bills that they would have paid if each could have filed singly. Similarly, a married couple receives a “marriage bonus” when the sum of the individual tax liabilities had they filed singly is greater than their tax liability under a joint return.