You know, don't push the button, don't push the button, don't push the button, and then some socko finish. I was pleasantly surprised by how the book bobs and weaves and is a lot more active and entertaining that just that. MILD SPOILER, so don't tell your four year old.
The late payment penalty applies to any portion of your federal tax that remains unpaid as of the due date, typically the tax filing date. The IRS imposes a failure-to-pay penalty of one half of one percent for each month or part of a month that the tax goes unpaid.
Chapter 131 of the Acts of 2010: Prior to July 1, 2010, the penalty was the lesser of $100 or 10% of the tax due. The new penalty calculation is 10% and will be applied to penalty assessments dated on or after July 1, 2010. Documentation to Submit with Abatement/Amended Tax Return (Personal Income): Federal Change Abatement Resulting from IRS Audit: