Last minute tax guide

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NEW YORK (CNNMoney.com) -- The clock is ticking. It's April 15th. And if you're still crunching the numbers, here's your last minute tax guide.

1. E-file

Over 77 million people filed electronically so far this year according to the IRS. And e-filing is supposed to break records this year.

And there's good reason people are going to their computer to pay their taxes. E-filing is faster, software programs can check for math errors and you get your return a lot more quickly if you electronically file. But ... there's always that lingering worry that maybe your computer will crash at the last minute or the IRS Web site will be unable to handle all those electronic 1040s. We put that question right to the IRS Commissioner Douglas Shulman who said the IRS is ready for all those returns this year.

2. Avoid errors

And filing your taxes last minute means there's more room for error. Here are some of the most common mistakes:

• Math errors
• Incorrect Social Security numbers
• Not signing your return
• Forgetting to sign the check

Remember, these errors can delay any refund you're entitled to.

3. Find a post office

If you decide to send in your taxes the old fashioned way, you're really under the gun here.

But good news! A lot of post offices have extended hours on tax day. To find a post office that's open later near you, go to usps.com.

And remember, as long as you have your taxes postmarked by April 15th, your return is considered filed, so forget about sending your taxes by certified mail.