Late Payment of Tax

irs.gov -

Late Payment of Tax

Generally, the penalty for not paying tax when due is ½ of 1% of the unpaid amount for each month or part of a month it remains unpaid. The maximum penalty is 25% of the unpaid amount. The penalty applies to any unpaid tax on the return. Any penalty is in addition to interest charges on late payments.

If you include interest on either of these penalties with your payment, identify and enter these amounts in the bottom margin of Form 1041, page 1. Do not include the interest or penalty amount in the balance of tax due on line 27.