The IRS reports that up to 20 percent of Americans wait until the last week to file. Just something to think about as you rush around on tax day trying to get everything done.

But make sure you do get everything in on time. Because once you are late with your taxes, you've opened a Pandora's box that can get worse with each passing day -- literally.

The IRS will start charging you interest payments, compounded daily, as soon as you are late. Then there are the penalties for filing late, which varies depending on how much you owe and how late you are.

While you can file for a six-month extension using Form 4868, you still need to file that form and pay any tax you owe by the regular filing deadline.

Really, it's much better to get it all over with and not end up paying more to the IRS than you need to.

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