If you’re a newlywed, you may be wondering whether it’s best to file taxes as single or married. But except for a few special cases. The decision is easy: if you’re married on the last day of the tax year, you file as married. You can choose between married filing separately or married filing jointly, but filing as single is no longer an option. In many circumstances, deciding between married filing separately and married filing jointly is just a matter of calculating things both ways and choosing the one that gives you the greatest tax benefits. The IRS has a very clear page on their website about filing status that goes into detail for each type, including head of household.
Remember that how you file has no relationship to what you put on your withholding form where you work. Also, your employer company won’t automatically change your information just because they know you’ve gotten married; you need to fill out a new form. (You should make sure that it correctly reflects your actual status; either single, married, or married but withhold at a higher single rate, but if you haven’t changed it yet don’t panic, just get it done.) The IRS withholding calculator might be helpful with that.