The IRS may have moved the tax deadline one day (to Wednesday, April 18), but if you haven't filed taxes yet, you'll still need to file and extension.

If you have to file an extension, it is very simple. You can do it online.

Mark Weech, CPA at Weech Financial said it will take you just about 10 minutes, and it's best to have your 2016 tax return nearby when you file.

Just go to the IRS website and click on "File an extension." That will take you to a link that lets you "e-file an extension for free."

Click on that link, and it will take you to a page listing several services the IRS has approved to file the extension.

But keep in mind, if you don't think you owe any money, then you don't have to stress about the extension.

"If you don't owe money, the extension deadline doesn't really mean anything to you, because you're just delaying you getting your refund back," said Weech.

On the other hand, if you do owe money, and you don't file the extension, you can be walloped by two penalties and interest.

The first penalty is the late filing penalty. It will cost you five percent of what you owe every month you don't file until you get capped at 25 percent.

The second penalty is the late payment penalty, which is not as severe.

On top of that, you have to pay interest. So if you think you owe the IRS money, file that extension ASAP!