Saying `I Do' To Tax Planning / the IRS cares about your wedding date almost as much as you do.

Kelly Phillips Erb for Forbes writes: Thinking of getting married? Choosing a wedding date is a big deal. You need to consider the time of year, the availability of your venue, how long it might take you to find the perfect dress – and what the tax consequences might be. Yes, the tax consequences. It turns out that the Internal Revenue Service cares about your wedding date almost as much as you do.

In order to figure out whether the time of your wedding makes good tax sense, you must understand a few basics about filing status. There are five filing statuses: Single, Married Filing Jointly, Married Filing Separately, Head of Household and Qualifying Widow(er) with Dependent Child. When figuring yours, the most important concept is this: for filing purposes, our marital status is determined as of the last day of the tax year. It doesn’t matter if you get married on March 1 or December 31 – you’re married for the whole tax year so far as the IRS is concerned.

With that in mind, here are a few reasons you might want to postpone, or move forward, your wedding date (or not say “I do” at all).

You might want to postpone your wedding date if:

You’re very sick or expecting an expensive medical procedure. The threshold for claiming medical expenses is now 10% of adjusted gross income (AGI) as compared to 7.5% of AGI in 2012. That means that, in addition to the requirement that you itemize your deductions, your qualifying medical expenses must exceed 10% of your AGI before you can claim the first dollar: the higher the AGI, the higher the threshold. Getting married means that your combined incomes will boost your AGI and as a result, the threshold for medical expenses will also increase. If you’re expecting high medical bills, the best situation from a tax perspective is to have a low AGI – which might be best accomplished with one income (in the alternative, you can get married and file separate returns assuming you have enough itemized deductions to split).

Your former spouse died during the year. If your spouse died during the year, you are considered married to your former spouse for the whole year for filing status purposes. However, if you remarry before the end of the tax year, you will file as married with your new spouse; your deceased spouse’s filing status will be married filing separately for that year. Depending on your former spouse’s financial circumstances – and assuming you’re the primary beneficiary of his or her estate – postponing your new wedding until next year may result in a lower tax bill.

You’re expecting to pay a great deal of unreimbursed employee business expenses, job search costs, or tax planning and preparation fees. Like medical expenses, these expenses are also subject to a floor before they can be allowed. Miscellaneous itemized deductions can only be claimed to the extent that they exceed 2% of your AGI. As before, the best situation from a tax perspective is to have a low AGI – which might be best accomplished with one income (in the alternative, you can get married and file separate returns assuming you have enough itemized deductions to split).

You’re expecting a one time financial windfall. If you’re about to cash out stock options or get a large bonus, it might pay to wait to get married if your spouse is working and earning a nice income. While filing as married filing jointly can work to your advantageous if one spouse makes more than the other or doesn’t work at all, it can result in a negative tax result if you both make good money. Since our income tax system is progressive, adding wages at the top means that those dollars are taxed at the highest tax rate. If you can push off your wedding date and get married after a temporary boost in income, you could potentially save thousands of dollars in tax.

You’re expecting a lot of deductions. The limitation for itemized deductions, sometimes called the Pease limitations, begins with incomes of $254,200 or more ($305,050 for married couples filing jointly). If you expect to have a lot of deductions in a particular year, you may lose out if your combined incomes push you over those limit. The limitations are essentially the same as an increase in the top marginal tax rates.

You might want to move your wedding date forward if:

You’re expecting. No, I’m not being old-fashioned. You are allowed one exemption for each person you can claim as a dependent.
If your child meets the rules to be a qualifying child of more than one person – because you’re not married – only one person can actually treat the child as a qualifying child. Depending on your finances and living arrangements, filing as single (or head of household) may not be as beneficial as claiming the child together as married filing jointly.

You’re terminally ill. For purposes of the federal estate tax (as well as most state estate and inheritance taxes), property that is included in the gross estate and passes to your surviving spouse is eligible for the marital deduction. That means that property is not subject to death taxes: property which passes to non-spouses can be taxed as high as 40%. It may be morbid but it’s generally tax advantageous to die while married.

You’re thinking about quitting your job. Filing as married filing jointly makes the most financial sense when one spouse makes more than the other – or if one spouse doesn’t work. You get the benefit of a “double” exemption as married filing jointly and tax brackets are wider – meaning that you can make more money and pay at a lower tax rate that if you were each filing as single. In other words, combining unequal incomes could bring higher wages into a lower tax bracket.

You’re the victim of a flood, theft or other casualty. As with medical expenses, you must itemize your deductions in order to claim the casualty theft loss. Depending on your financial picture, it might be easier to meet the threshold for itemizing ($12,200 for 2013 and $12,400 for 2014) by combining expenses for deductions.

You’re selling your home. When you sell your primary residence, you can exclude up to $250,000 in gain – or $500,000 for married taxpayers. To qualify, you must have owned your home for at least two out of the past five years and the home must have served as your primary residence for two of the past five years. For purposes of the exclusion, only one spouse has to own the house for two of the past five years but both must have lived in the house for at least two years. If you’re planning on selling, and you were living together even if you weren’t married – you can meet the residency test and claim the entire $500,000 once you are married. The result? Thousands of dollars of tax savings.

You might not want to say “I do” if:

You receive Social Security. If your only source of income is Social Security benefits, your benefits are generally not taxable. If you receive other income, your benefits may be taxable if your modified adjusted gross income (MAGI) is more than the base amount for your filing status. The base amount for taxpayers who file as married filing jointly is $32,000 compared to $25,000 for taxpayers who file as single. Depending on the level of other income, getting married can result in making your Social Security benefits taxable.

You have concerns about your potential spouse’s tax returns. When you file a joint return, each taxpayer accepts equal responsibility for any tax due, as well as any related interest or penalties. If you’re worried about what might end up on that return, you can opt to file as Married Filing Separately. But once you’re married, no matter how much you try to keep your tax records and finances separate, you are necessarily affected by the consequences. For example, if your spouse is subject to huge penalties – even if you are not legally responsible for those penalties – those obligations affect how you spend your household money.

Decisions about family and marriage are huge and important. And I’m not suggesting that you should choose your wedding day for tax reasons – there’s enough to think about without relying on that as an absolute. But financial considerations should be a part of the bigger picture. Talking about money and taxes is part of being married. Why not start now and make it part of getting married?