How Filing Tax Extensions Works

Some people in the United States file their federal income tax returns before April 15 -- sometimes long before. Others file their returns at 11:50 p.m. on April 15.

But you may need even more time. If you haven't received all of your 1099 or W-2 forms -- records of how much income you have received from various sources -- you may not have all the numbers you need to fill out your 1040. Or maybe you don't have the numbers from your 1098 interest forms. Or maybe your tax return is just enormously complicated and you haven't had time to work on it.

Whatever the case, the worst thing you can do is to not file for an extension. Fortunately, it's really very simple: Fill out IRS Form 4868 and mail it in by April 15.

Filling out Form 4868, available on the IRS website, can give you an extra six months to file most federal income tax forms, including the 1040, 1040A, 1040EZ, 1040NR and 1040NR-EZ. If the IRS grants you an extension, your new filing deadline becomes October 15.

Form 4868 is simple, a mere nine lines long. You'll need to provide:

You can file Form 4868 by mail, over the Internet, via tax software or even by telephone.

The IRS highly recommends making a payment on your estimated tax liability when you file Form 4868, because a filing extension is not a payment extension. Any tax you owe begins to accrue late payment penalties and interest after April 15. If you can't pay all of it, you have the option of paying whatever you can manage at the time. Every little bit helps reduce penalties and interest.

If you don't have enough money in your bank account to pay the estimated tax, you have the option of paying taxes by credit card. Of course, whether this is wise depends on your financial situation and your credit card's interest rate.

Oops. You didn't file on time, and you didn't file for an extension. What will the IRS do to you? Read on.

Back in high school, when you turned in a term paper late, your grade was probably reduced by your tardiness. The Internal Revenue Service operates on the same principle.

Even if you only need an extra week to file your return, use Form 4868 to file for an extension. A week may not seem like much, but you're better off avoiding the late penalty. U.S. taxpayers who live and work abroad have an automatic two-month extension to file their tax returns, putting their filing deadline at June 15. They do not have to file Form 4868, but when they file their returns in June, they must include proof that they do indeed live and work abroad. Note that for this extension, Puerto Rico does not count as "abroad." The IRS also extends an automatic 180-day extension to military personnel serving in combat zones and a one-year extension to victims of a "Presidentially declared disaster or a terroristic or military action" [source: IRS].

As mentioned, filing an extension does not suspend interest from accruing on your tax liability, nor does it necessarily prevent penalties for not paying by the due date.

The IRS assesses a late-payment penalty if you do not pay 90 percent or more of your unpaid tax by April 15, even if you file Form 4868. For example, let's say you owe $5,000 in taxes:

">$5,000 x 0.90 = $4,500

If you don't pay at least $4,500 when you file Form 4868, the IRS will assess a late-payment penalty. The penalty is 0.5 percent of the amount you owe per month. This penalty continues until you have paid the maximum 25 percent penalty. Using the example above, the late-payment penalty would be:

$5,000 x 0.005 = $25 per month up to 25 percent, or $1,250

So the sooner you pay off the unpaid taxes, the less you will pay in penalties.

If you file your tax return on time and apply for an installment agreement, the IRS reduces your late-payment penalty to 0.25 percent per month.

$5,000 x 0.0025 = $12.50 per month.

If you do not apply for the filing extension, the late-filing payment fee is 4.5 percent of the unpaid tax per month up to five months.

$5,000 x 0.045 = $225 per month

In addition to late-payment penalties, any tax you owe after April 15 will accrue interest. Remember, a filing extension is not a payment extension. This interest, which is compounded daily, will continue to accrue for as long as you owe tax. As with late-payment penalties, the sooner you pay off the tax, the less interest you'll pay.

The interest rate on unpaid tax is "the federal short-term rate plus 3 percent." As of the second quarter of 2008, the interest rate on unpaid tax (for individual taxpayers, not businesses) is 6 percent [source: IRS].

Let's take the above example again, in which you owe the IRS $5,000. We'll calculate the interest for one month.

­Interest

$5,000 x .06 = $300

Penalty + Interest

$25 + $300 = $325

So you would owe $325 for every month you don't pay on top of the $5,000 in taxes you already owe the IRS. Now, this simple example doesn't take into account any payments you make on your tax during the year, but it should give you an idea of how large tax debt can grow and grow. And making payments on your unpaid taxes is what an installment agreement is all about. Check it out on the next page.

You set up payment plans on cars, houses and other expensive pieces of property. You can do the same thing with federal income taxes. The IRS calls this plan an installment agreement.

If you can't pay the total amount of income tax you owe, you can file Form 9465 to break the unpaid amount into monthly installments.

Like Form 4868, Form 9465 is not very complicated. The information you need to provide consists of:

The IRS is obligated to accept your installment agreement if:

If you don't meet these qualifications, the IRS may adjust the terms of your installment agreement.

The fee for setting up an installment agreement is:

[source: IRS]

If you are supposed to get an income tax refund in any tax year while you are making payments on an installment plan, your refund will be applied toward what you still owe the IRS. Yes, the IRS will get its money.

As with any other debt, missing a payment or multiple payments can make for a bad day. Not paying could put you in danger of defaulting on the installment agreement. And when the IRS does not get its money, it goes after its money.

The IRS will send you a Notice of Federal Tax Lien when it has acquired the right to seize your personal property (your house, your furniture, your antique galleon). When the IRS sends you a Notice of Federal Tax Levy, it will grab your property and auction or sell it to satisfy your tax debt.

The two things to remember in your dealings with the IRS are deadlines and payment. Pay what you owe on time, whether on an installment agreement or not, and you'll be fine.

If you'd like to know more about filing extensions and related topics, follow the links on the next page.