Income taxes for individuals and corporations are due by a certain date. An IRS late tax penalty is the amount of money owed as the result of failure to pay by the stated time. A late tax penalty may be considered under several categories. It may be looked at as the result of failure to pay. The amount of late tax penalty for this type of late payment is 0.50% of 1%. If, however, the late tax payment follows the issuing of a Notice of Intent to Levy, the amount of the rate increases to 15. In neither case can the amount charged exceed 25% of the unpaid taxes. Filing late, usually amounts to a 55 charge for each month. The rate cannot exceed 25%. The exception is filing late due to fraud. The rate charged is then 15% each month or part of the month. If you fail to file a return until 60 days has passed, the IRS late tax penalty is different. The minimum payment possible is smaller than $135 or 100% of the unpaid tax. You may be able to obtain an exception or reduction if you can prove to the IRS you did not do so out of willful neglect. You can base your argument on "reasonable cause."