Penalty for Failure to Timely File Return: If a taxpayer is required to file an income or excise tax return and fails to timely do so, a late filing penalty may be assessed. The penalty is 5% of the amount of unpaid tax per month (or partial month) the return is late, up to a maximum of 25%. A minimum penalty of $435 may apply for returns over 60 days late. The minimum penalty is the lesser of $435 or 100% of the tax due on the return.
Penalty for Failure to Timely Pay Tax: If a taxpayer fails to pay the balance due shown on the tax return by the due date (even if the reason of nonpayment is a bounced check), there is a penalty of 0.5% of the amount of unpaid tax per month (or partial month), up to a maximum of 25%.
Penalty for Failure to Timely Pay After Issuance of Notice: If a taxpayer fails to pay any additional tax assessed by the IRS (usually as a result of an audit which can be avoided) the taxpayer may be liable for a penalty equal to 0.5% for each month (or partial month) during which the failure continues, if the amount is not paid within 21 calendar days after the date of an IRS notice demanding the payment. If both the failure to file and the failure to pay penalties apply during the same month, then the failure to file penalty is reduced by 0.5% each month. The 25% cap above applies to the 5% late filing penalty and the 0.5% late payment penalty together. The late filing penalty may be waived or abated on showing of reasonable cause for failure. The failure to file penalty is imposed and starts to accrue interest from the due date of the return. The failure to pay penalty is imposed when a taxpayer pays the taxes after payment was due, computed from the date prescribed for paying the tax. The Internal Revenue Service advises that if the taxpayer wants to compute the penalty for failure to timely file and the penalty for failure to timely pay the tax shown on the return, or the interest, and to pay those items at the time the return is filed, the taxpayer can "identify and enter the amount in the bottom margin" on the second page of
Form 1040. The IRS advises that the taxpayer "not include interest or penalties (other than the estimated tax penalty)" in the "Amount Owed" line of the form. ==Accuracy related penalties==