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