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Late filing penalty calculator
Two different penalties, two different maths. Partnership and S-corp returns are penalised per owner, per month, even when no tax is due. Returns with a balance owing are penalised as a percentage of the tax. Pick the one that matches your return.
- Built by a team of Certified Accountants, CPAs and Enrolled Agents
- 2026 figures
- Estimate only, not advice
Estimate only. 2026 figures: $255 per owner per month for late 1065 and 1120-S returns (maximum 12 months); failure-to-file 5% a month up to 25%, reduced to 4.5% in months where the failure-to-pay penalty also runs; failure-to-pay 0.5% a month up to 25%; minimum late filing penalty $525 once more than 60 days late. Interest compounds daily; the calculator approximates it.
Why a return with no tax due can still cost thousands
Partnership and S-corporation returns are information returns: the entity usually owes nothing, the owners pay the tax on their own returns. That is exactly why the IRS penalises them differently. Instead of a percentage of tax, the penalty is a flat amount per owner, per month, for up to twelve months. Two partners, five months late, is ten owner-months at $255 each: $2,550 for a return that carried no tax at all.
Owners find out late because nothing else goes wrong. No bill, no bounced payment, no missing refund. The notice arrives months later, usually addressed to the entity, sometimes to a registered agent address nobody checks.
Failure to file versus failure to pay
For returns with a balance (Form 1120, Form 1040, and the pro forma 1120 attached to Form 5472), two penalties run in parallel. Failure to file is the expensive one: 5% of the unpaid tax for each month or part of a month, capped at 25%. Failure to pay is 0.5% a month, also capped at 25%. When both apply in the same month, the filing penalty drops to 4.5% so the combined rate stays at 5%. Once a return is more than 60 days late, a minimum penalty applies: $525 for returns due in 2026, or the full tax if that is less.
The practical lesson: file even if you cannot pay. Filing stops the 5% penalty and leaves only the 0.5% one running. An extension does the same for the filing penalty, but not for the payment penalty, which is why an extension should travel with a payment.
Interest is separate and does not stop
Interest accrues on the unpaid tax and on the penalties from the original due date, compounded daily, at the federal short-term rate plus three points. It is not waived with a penalty abatement and it does not pause while the IRS processes anything. The calculator uses a flat annual rate you can change.
Getting a penalty reduced
- First-time abatement. Available when the entity has filed and paid on time for the previous three years and has no other open penalties. It is an administrative waiver, granted on request, and the most common route.
- Reasonable cause. A written explanation of what prevented filing: illness, disaster, reliance on a professional who failed, records destroyed. Vague explanations are declined; specific, dated ones with evidence are often accepted.
- Small partnership relief. Partnerships with ten or fewer partners who are all individuals or estates, where each partner reported their share on time, can qualify for relief under Revenue Procedure 84-35.
- Pay the tax first. Abatement requests go better when the underlying tax is paid, because the failure-to-pay penalty stops growing and the file looks like a one-off.
We prepare the late return and the request together. The IRS decides; we do not promise the outcome, and anyone who does is selling something.
Questions people ask
Is the per-owner penalty charged even if the S-corp had no income?
Yes. The 1065 and 1120-S penalty is for the late return itself, not for tax. A dormant partnership that skips its return is penalised the same way as an active one.
Does an extension avoid the penalty?
An extension filed by the original due date avoids the failure-to-file penalty for the extension period (six months). It does not extend the time to pay, so the failure-to-pay penalty and interest still run on any balance.
What is the maximum?
For 1065 and 1120-S returns: 12 months times $255 times the number of owners. For failure to file and failure to pay: 25% of the unpaid tax each, so up to 47.5% combined, plus interest.
Can I just wait for the notice and then pay?
You can, but the notice usually arrives after several months of penalties have accrued, and by then first-time abatement is your only clean route. Filing before the notice is cheaper and looks better in any reasonable-cause request.
Do state penalties work the same way?
No, and they vary widely. Some states charge a percentage of tax, some a flat late fee, and most revoke good standing for a missed annual report on top. Your state page lists what applies.
What does it cost to have you file a late return?
From $99 per return, plus the penalty-relief request where reasonable cause exists. Late years are quoted per year, in writing, before we start.
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