Among the many things that change when you say "I do" is your federal income tax situation. Everything -- from how your employer withholds taxes from your paycheck to your filing status on your income tax return -- must be adjusted. By making some of your tax decisions in advance you can smooth out the impact of the transition from being single to being married.
The date of your wedding might be significant for celebrating your anniversary in years to come, but as far as the Internal Revenue Service is concerned it is irrelevant for tax purposes. The IRS doesn't care what date you got married. It only cares what year you got married. Whether you tied the knot on Jan. 1 or Dec. 31, as long as you are married by the end of the year, the IRS considers you to have been married for the entire year.
Your employer withholds taxes from your paycheck based on information you supply when you fill out your Form W-4. Factors that affect the amount withheld include your marital status and the number of allowances you claim. If you don't fill out a new Form W-4, your employer will not adjust the amount withheld from your paycheck. As a married individual you can reduce your tax withholding rate by checking the "Married" status. You have the option of checking the "Married, but withhold at higher Single rate" status. You can reduce the amount of taxes withheld by increasing the number of allowances you claim. You can claim an additional allowance for your spouse and any dependent children that join your family as a result of the marriage.
When its time to file your federal income tax return you have a decision to make as a couple regarding your filing status. Married individuals have the option of filing either a joint return or separate returns, but both spouses must file using the same method. Most married couples file joint returns because it typically provides a lower combined tax obligation. You can file separate returns, but you lose certain benefits, for example you can't claim the earned income credit or the deduction for student loan interest. Joint returns make both spouses liable for the entire tax obligation, so if you want to be solely responsible for your own taxes, you'll need to file separate returns.
When it comes to federal income taxes, married couples who file joint returns might experience either a marriage tax bonus or a marriage tax penalty. In most cases you get a bonus, because you get to combine both of your incomes and your deductions, even if only one spouse worked or if one spouse earned significantly more than the other. If both of you earned high incomes, you might get hit with the so-called marriage tax penalty. This happens when your combined incomes put you into a higher tax bracket than you would have been in as single people, because at higher income levels the tax brackets for joint returns are not twice as much as the tax brackets for single returns. The IRS recommends figuring your tax return using both the joint and separate filing statuses, then filing your return using the status that provides the lowest combined tax obligation.