I've always assumed there was some sort of tax benefit to filing U.S. federal taxes jointly with a partner. Now that I'm filing taxes for the first time after getting married, however, I see that it's not so simple. There is a tax benefit if two partners have disparate individual incomes, but there is a penalty if both partners have roughly equal incomes. The following graphic shows the difference in the taxes between filing jointly and separately as percentage of joint income:
The values represented in the diagram are the difference between the total amount of taxes that a couple would owe (with the 2011 federal U.S. tax schedule) if they were to file jointly or file separately, given as a percentage of the couple's total income. For example, if the lower-earning partner earns $25,000 and the higher-earning partner earns $75,000 they owe $18,200 if filing separately and $17,250 if filing jointly, resulting in a marriage benefit of $950, or about 1% of their total income.
A little googling revealed that the whole “marriage penalty, marriage benefit” story isn't quite so simple; for example, married couples filing jointly can enjoy preferential estate-tax treatment. However, if the benefits of filing jointly are not relevant, many married couples may pay less tax by filing separately.
Contributors to “Taxes after marriage”
Wondering why there are multiple contributors? At DsA, we work in teams. Even on blog posts, we often work together or ask for others to take a look at the post before we post it. When we do that, the pictures of those that wrote the post are larger than those that edited the post.