Best thing to do if you're late to file is to pay and file your tax return as soon as possible.

If you fail to file your tax return by the deadline, you could face a penalty of 5 percent of your unpaid tax bill, plus interest, for each month the return is late - until the penalty hits 25 percent of what you owe.

If you file but fail to pay your taxes, the penalty is only half a percent of your unpaid tax bill, plus interest, each month.