What happens if I file or pay my taxes late?

Two different additions

• Filing late and paying late are separate additions to tax. The one for filing late is the larger per month; both are capped.
• Both are figured on the tax still unpaid: tax paid on time and credits on the return reduce the base.
• When both apply in the same month, the filing addition is reduced by the payment addition for that month.

What can take it away

• Neither applies if the failure was due to reasonable cause and not willful neglect.
• A return more than 60 days late carries a minimum filing addition, unless reasonable cause applies.

What it turns on

• how late the return was filed and whether an extension was in place
• how much tax was still unpaid on the due date
• the reason the return or payment was late

What would make it not apply

• the delay was due to reasonable cause and not willful neglect
• no tax was owed after payments and credits

The law, quoted

Sources: IRC §6651. Each passage below is copied from the document VALID fetched, with the start of its SHA-256 fingerprint.

(2) to pay the amount shown as tax on any return specified in paragraph (1) on or before the date prescribed for payment of such tax (determined with regard to any extension of time for payment), unless it is shown that such failure is due to reasonable cause and not due to willful neglect, there shall be added to the amount shown as tax on such return 0.5 percent of the amount of such tax if the failure is for not more than 1 month, with an additional 0.5 percent for each additional month or fraction thereof during which such failure continues, not exceeding 25 percent in the aggregate; or

IRC §6651 — In case of failure- · law in effect September 29, 2026 · fingerprint 84d6a9b8724c