If you are required to pay a tax return, you must do so by the due date of the return (including extensions). Failure to file your tax return timely may lead to the imposition of a penalty that increases each month that the return is late. The penalty is 5% of the tax not paid by the due date for each month or part of a month that the return is late. The amount of this penalty, however, is capped at 25% of your tax liability.
If you are subject to both the failure to file and failure to pay penalty, the IRS cannot impose both penalties in full. The failure to pay penalty will be imposed to the full extent, however, the failure to file penalty will be reduced by the amount of the failure to pay penalty for any months both penalties apply. For taxpayers who are more than 60 days late in filing a return, the penalty will not be less than $100 or 100% of the tax balance, whichever is less.