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What are the Tax penalties and interest?
If you owe taxes, the Internal Revenue Service will calculate penalties and interest on the amount owed. If you have a refund, the IRS may pay you interest on the delayed refund.
Generally, interest is charged on any unpaid tax from the due date of the return until the date of payment. The interest rate is determined every three months and is the federal short–term rate plus 3 percent. Interest is compounded daily. If you file on time but don't pay all amounts due on time, you'll 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 from the due date, until the tax is paid in full or the 25% maximum penalty is applied. If you owe tax and don't file on time, the total late-filing penalty is usually five percent of the tax owed for each month, or part of a month that your return is late, up to five months. If your return is over 60 days late, the minimum penalty for late filing is the smaller of $100 ($135 for returns required to be filed after December 31, 2008) or 100 percent of the tax owed.
The penalties for filing and paying late may be abated if you have reasonable cause. If you're billed for either penalty or feel you have reasonable cause, send your explanation along with the bill to your service center, or call the IRS at 800–829–1040 for assistance. Interest charges may not be abated; they continue to accrue until all assessed tax, penalties, and interest are paid in full. Generally, any reasonable cause exception to the penalty for failure to pay tax cannot be determined until the tax is first paid in full.