For Newlyweds, Arguments For and Against Filing Taxes Jointly

NEW YORK -- ( MainStreet) -- So you got married in 2011? That's great, but the Internal Revenue Service doesn't have all year for you and your spouse to decide how you'll file your taxes.

There is one basic truth for newlyweds during tax season: Whatever your marital status was Dec. 31 is what the IRS considers you for all of 2011. From there it gets a bit more complicated.

Joint tax filing is usually the best way to go, but medical bills and "risky spouses" can get in the way.

A married couple's first kiss after taking their vows essentially kisses both of their "single" tax filing statuses goodbye. From here on in, they're left with two options: married filing jointly and married filing separately. The former generally results in the lightest tax hit by giving couples a few breaks, including a credit for child- and dependent-care expenses, deductions for student loan interest and a lifetime learning credit. This wasn't always the case, but George W. Bush's tax cuts in 2001 and the Tax Relief Act in 2010 helped expand the lower tax brackets for joint filers and make it a bit easier on big earners and their low-earning spouses.

"Historically, two singles cohabiting would pay less than a married couple, but that was changed with the Marriage Penalty Relief Act," says David B. White, certified public accountant and president and founder of David B. White Financial in Bloomfield Hills, Mich. "Generally speaking, married filing jointly is going to be lower than married filing separately, especially if there's an imbalance of earnings where you would forfeit expenses and deductions for the person who doesn't have much income."

A couple's tax decision also has a great effect on their plans for retirement savings. When a couple files jointly and one spouse isn't working, the working spouse can make a contribution for the nonworking spouse that wouldn't be allowed if they're filing separately. Also, the $10,000 limit on Roth IRA contributions for those filing separately is much lower than it is for joint filers.

Filing separately doesn't help when it's time to balance the books, either. Couples filing jointly can deduct $3,000 in capital losses against ordinary income. Those filing separately, however, can deduct only $1,500 in losses and can't use one spouse's losses to offset another's gains.

It's a big reason why only 4.5% of married couples filed separately in 2009, the last year for which data were available. Married couples filing separately made up less than 2% of all returns filed that year, but that didn't necessarily mean they were making the wrong call.