Penalties and interest for paying and filing taxes after the due date

Interest, compounded daily, is charged on any unpaid tax from the due date of the return until the date of payment. That rate is determined every 3 months. For 2013 the interest rate is 3%. In addition, if you filed on time but did not pay on time, you will generally have to pay a late payment penalty of one half of one percent of the tax owed for each month, or part of a month, that the tax remains unpaid after the due date, up to a maximum of 25%. The one half of one percent rate increases to one percent if the tax remains unpaid after several bills have been sent to you and the IRS issues a notice of intent to levy. If you owed tax and did not file on time, the penalty is even higher. The combined late filing and late payment penalty is 5% of the tax owed for each month, or part of a month, that your return was late, up to a maximum of 25%. If your return was over 60 days late, the minimum penalty is the smaller of $100 or 100 percent of the tax owed.