The tax deadline arrives, and you can't pay your federal income tax bill. What do you do?

First, relax. You are not the only one. A 2012 General Accounting Office report found individuals owed $258 billion in unpaid federal taxes, and businesses owed another $115 billion. While you can't realistically hope your tax bill will get lost in all those zeroes, the IRS offers several options to get square with the feds.

Second, be sure to file your return. "If you have all your information, file a return," stresses Doug Stives, a CPA and accounting professor at Monmouth University. "If you don't have all the information, file for an extension. But definitely file."

The economics of filing even without paying are compelling. Basically, notes Kevin Gallegos, vice president with consumer financial services firm Freedom Financial Network, it costs more to file late than it does to pay late. The penalty for not filing is 5% of the tax due per month, up to 25% of the tax due.

"If you file more than 60 days late, you might face a penalty equal to the taxes you owe -- doubling your payment," Gallegos says. By comparison late payment is a bargain. The IRS charges interest on unpaid taxes of 0.5% per month, or 6% a year.

Still, when you file, if at all possible you should send partial payment, Stives says, even if it's $100 toward a $10,000 debt. If nothing else, when payment clears your bank, you'll know the IRS received your return. And paying something now reduces interest and penalties that will accrue to whatever you leave unpaid.

One quick, easy and cost-effective way to deal with an overwhelming tax bill is to take out an IRS installment loan. These can be done online if you owe $50,000 or less and have filed all required returns. There's a $52 fee if you have monthly payments directly debited from your account. You can take up to seven years to pay and the annual interest rate is 3%, plus a late payment penalty of 0.25% per month.

You may consider financing your tax payment with a credit card. However, that is likely to mean higher interest rates, as well as hefty fees for late payments. Loans from friends and family are also potential sources. But Stives says there's no reason to fear an IRS loan. Having an IRS loan won't, for instance, increase your chances of being audited. "They don't like to loan money, but they will," he says.

You might even get a break on penalties if you meet certain requirements. "If your tax debt exists because of 'reasonable cause,' the IRS might waive or reduce penalties," Gallegos says. “Reasonable causes may include a death in the family, serious illness or financial records lost in a natural disaster." To request a waiver, contact the IRS.

If you owe too much to take out an installment agreement, can't foresee making payments or already have an IRS loan -- there is a limit of one at a time -- you could offer to pay whatever you can in exchange for settling all or part of your tax debt. These offers in compromise, as they're known, are difficult to obtain, Stives warns. "Unless you really have nothing, they'll tell you you have to pay," he says.

Tax law continually evolves, and just last year the amount taxpayers can pay via installment loan was doubled, from $25,000 to $50,000. Not all the news is good, however. A law passed in December 2015 lets the IRS revoke or deny a passport application to anyone who owes $50,000 or more and isn't in a payment plan, Gallegos says.

One thing you probably should not do is call an accountant for help at the last minute on the busiest day of the tax preparation year. "You're too late," Stives says. "If any CPA takes your phone call on April 15, there's something wrong."