The mad dash

When runners in the Boston Marathon spot the finish line, they know the end is near. But taxpayers racing to this week's deadline for filing tax returns have an option.

If they run out of steam before finishing up by midnight Tuesday, they can stop to catch their financial breath and start again later.

"We tell people not to rush," says Peggy Riley, an Internal Revenue Service spokeswoman. "You can file for an extension and take time to do the best return you can."

Through the end of the March, the IRS has received about 1.8 million Massachusetts returns, or about 60 percent of the projected total. The IRS expects about 181,000 Massachusetts filers to apply for extensions. The deadline for getting a six-month extension is the same initial April 17 deadline for filing a return.

A big catch is that federal and state extensions are for filing your return, not for paying any tax you still owe. You face interest and possible late payment penalties on amounts not paid by the original deadline. Also required is that you at least estimate any tax you might owe.

Still, an extension can protect you from a larger penalty for not filing on time. To limit interest and penalties, send a tax payment with the extension request. If you file late and are due a refund, there's generally no penalty even if you do not get a formal extension.

Here are some other things to keep in mind as you finish up.

Double check. Look at the details. Forgetting to sign a return, for example, makes it invalid -- both spouses must sign a joint one. Also, check the math, be sure to attach W-2 withholding statements, and if asking for direct deposit of a refund, confirm your bank account and routing numbers, says the IRS in relating common goofs.

New stuff. New breaks and glitches in the forms can add to deadline angst. The IRS says many people -- nearly a third -- are not claiming a widely available, one-time refund of a telephone excise tax. Most people are opting for a standard amount of $30 to $60, based on the number of personal and dependent exemptions on their returns. You can claim the credit on line 71 of the 1040, line 42 on the 1040A, and line 9 on the 1040EZ.

Also easy to miss, says attorney Donna LeValley, an editor at the J.K. Lasser tax guide, are deductions that lapsed last year and were renewed by Congress too late to be included in tax forms.

Affected are deductions for college tuition, school teacher expenses, and sales tax, which can be taken instead of a deduction for payments of state income tax. The IRS website, tax software, and informed tax preparers have information for handling these items.

Go to the 1040 Central section at irs.gov by clicking the "individuals" tab and then "late legislation" and "tax law changes" for details about the deductions and how to claim them. A wealth of other guidance is also at the site.

Not too late. You may be able to do retroactive tax planning for retirement, notes Leo Bruette, a tax partner at BDO Seidman accountants.

The deadline for opening or contributing to an IRA for 2006 is also this Tuesday -- a cutoff that's firm even if you get an extension to file your tax return. Still, if you qualify and act fast, you can generate a 2006 federal tax write-off with a deductible IRA (there's no Massachusetts deduction) or, in the case of a nondeductible Roth IRA, you can bolster the accumulation of future tax-free income.

Extension, extension. If filing by Tuesday night seems out of the question, an extension buys time to gather records, decipher the rules, hire a pro, or just make up for procrastination. To get a federal extension, mail in form 4868, downloadable at irs.gov.

Or, you can do it with tax preparation software or in some cases through the IRS website's Free File program. You can do it by phone if you are also paying tax by credit card. Tax form instructions and the IRS website give details, or call the IRS at 800-829-1040.

Massachusetts taxpayers can get a six-month state extension with state form M-4868 (mass.gov/dor) or in some cases online or by phone. If you owe no additional tax or are due a refund, an extension is generally automatic with no form required. Details are available with Form 4868, online, or by calling 800-392-6089 or 617-887-6367 from out of state.

Woburn accountant Andrew Schwartz says many of his self-employed clients, drained after paying regular and estimated tax in April, get federal extensions even though they could file their returns on time. That's because a filing extension gives them six more months to make deductible deposits to a self-employment retirement plan for 2006.

Get help. Paying a tax preparer to do the work can ease the strain. H&R Block, for one, operates on extended hours in the final crush and some offices stay open around the clock, says spokesman Dan Smith. But while simpler returns with complete records can be done in the final hours, other latecomers may be handled by first getting an extension.

Certified public accountants and other high-end preparers typically shun last-minute projects and prefer an extension, especially for new clients. "CPAs do their best work when they have time to think," says accountant Cindy Brandt in Woburn.

It's in the mail. Few post offices stay open late to accept returns for postmarking by midnight, partly reflecting increased electronic filing, says postal spokesman Bob Cannon. The IRS projects that about 75 percent of Massachusetts returns will come in electronically.

If you must make a late-night snail mail run, the Fort Point postal facility near South Station in Boston is an option because it is regularly open 24 hours, which also makes it handy for those who want certified or registered mail for proof of mailing.

When using a mailbox, even at a post office, check if the last pickup is for later that day, says Cannon. If not, the postmark will be the next day.

And stick on enough stamps. "Some returns with several pages can exceed the 1-ounce limit of a regular stamp," warns Cannon. Returns with too little postage may be returned to you. FedEx, UPS, and DHL also offer IRS-sanctioned delivery options for last-minute returns.

So when do I get my refund? The average refund so far this year is $2,736, up $85 from a year ago. You can check on the status of your refund by calling the IRS Refund Hotline at 800-829-1954 or checking "Where's My Refund" at the IRS website.

If you file electronically, expect to get your refund within two to three weeks. If you mail in your return, it's now going to take six to eight weeks. Having a refund directly deposited to your bank account can also speed up the process.

If you owe taxes, you can pay by check or money order. But alternatives include paying by credit card -- with an additional fee -- or if you file electronically, having the money debited from your bank account.

For help with refunds and electronic and other payment options for Massachusetts state tax, you can go to the state tax website, call the Department of Revenue help line, or check the tax form instructions.

Running short? You may be able to work out a monthly installment payment plan with Uncle Sam. In some small cases, approval is virtually automatic. To apply, use form 9465. If the amount owed is up to $25,000, you can apply by going to the "online tools" section at the IRS website.