The IRS may reduce or remove certain penalties when the facts show reasonable cause and the applicable penalty rules allow relief. Reasonable cause is not a checklist—it is a narrative showing what happened, when it happened, how it prevented compliance, what you tried anyway, and how you recovered. A complete request pairs that timeline with contemporaneous records: medical documentation, disaster declarations, advisor correspondence, or third-party evidence that the event affected your ability to comply despite reasonable care.
What reasonable cause requires
Reasonable cause is evaluated penalty by penalty and fact pattern by fact pattern. The IRS examines whether you exercised ordinary care despite circumstances beyond your control. Document the specific event, its timing, its direct effect on the filing or payment duty, any steps you took to comply or mitigate harm, and the actions you took once the barrier lifted. Supporting records distinguish a credible request from a general hardship statement.
Financial difficulty alone does not establish reasonable cause for late filing or payment. Oversight, misunderstanding of the law, and simple reliance on a tax preparer generally fail. Accuracy-related penalties under IRC 6662 have a distinct reasonable-cause and good-faith standard where reliance on a competent adviser can matter, depending on the information provided and the particular issue. Estimated-tax penalties are governed by separate waiver rules and do not follow the reasonable-cause framework.
Build the causal timeline
Start with the precipitating event: serious illness, natural disaster, unavoidable absence, death of an immediate family member, or loss of records through fire or theft. State the date and describe how it directly impaired your ability to file, pay, or maintain accurate records. Next, show what you attempted: requested an extension, contacted the IRS, arranged partial payment, or sought professional help. Finally, explain recovery: when you regained capacity, how you brought the account current, and the date you filed or paid.
Attach third-party verification. Hospital discharge summaries, insurance claims, FEMA declarations, probate filings, and police reports anchor the timeline in documented fact. If a professional advised you, include the engagement letter, the specific question you asked, the written guidance you received, and proof that you disclosed all material facts. Explain what advice was actually sought and received; do not invent or backdate supporting records.
Choose the request path
| Situation | Check before choosing a route | Practical next step |
|---|---|---|
| Assessed failure-to-file or failure-to-pay penalty | Administrative relief and the specific reasonable-cause rules | Call the number on the notice with the notice and supporting records ready |
| Relief not approved over the phone | Whether a written Form 843 request is appropriate | Follow the current form instructions and explain the requested relief |
| Accuracy-related penalty | The distinct reasonable-cause and good-faith standard | Explain efforts to report correctly and any relevant adviser reliance |
| Estimated-tax penalty | Separate waiver rules; reasonable cause does not apply | Consult the IRS guidance for the particular estimated-tax penalty |
| Denied relief request | Appeal rights and deadline stated in the denial letter | Follow that letter rather than assuming a universal appeal route |
Some penalties can be resolved by phone if you reference the notice number and the representative agrees the facts warrant relief. If that route is unavailable or unsuccessful, prepare a written request. Form 843 is the standard vehicle: it requires the tax period, penalty type, abatement amount, and a statement of facts. Attach your timeline, supporting documents, and any correspondence. Confirm the mailing address in the current Form 843 Where To File table; notice-response claims generally use the notice return address.
The IRS may also apply First Time Penalty Abatement if your compliance history and the penalty type make you eligible. Administrative relief does not require proof of reasonable cause, so confirm eligibility before investing time in narrative assembly. If you receive a CP2000 notice proposing additional tax and penalties, address the underreporting separately; include any relevant explanation of the proposed penalty in the notice response as well as addressing the disputed tax adjustment.
Reasonable cause checklist
Assemble and verify each component before mailing:
- [ ] Penalty notice or account transcript showing assessment date and amount
- [ ] Narrative timeline: event date, direct effect on duty, compliance attempts, recovery date
- [ ] Third-party records: medical, legal, disaster, or professional correspondence
- [ ] Completed Form 843 with penalty type, tax period, and requested abatement
- [ ] Copy of filed return or payment history if penalty stems from late payment
- [ ] Explanation of how the event prevented compliance despite ordinary care and prudence
- [ ] Proof of current compliance: filed returns, payment arrangements, or full payment
Keep a complete copy. Track the submission and any IRS response instructions, and arrange follow-up appropriate to the notice and the case.
Does reasonable cause remove penalty interest?
When the IRS abates a penalty for reasonable cause, it automatically adjusts the related penalty interest. This does not waive statutory interest on the underlying tax or interest that accrued for other reasons. Only the interest directly attributable to the abated penalty is removed.
Can I appeal a reasonable cause denial?
Yes. The denial letter will specify your appeal rights and the office to contact. Follow the deadline and instructions in your specific denial letter. If the letter offers Appeals conference rights, submit a written protest. If it directs you to a different process, such as reconsideration or audit reconsideration, follow that path.
Does reliance on a tax professional always work?
No. For failure-to-file and failure-to-pay penalties, general reliance on a preparer does not establish reasonable cause. For accuracy-related penalties under IRC 6662, reliance on a competent adviser may support reasonable cause and good faith, depending on the particular issue and whether all needed information was provided. The standard is narrow and penalty-specific.
For tax firms
A structured reasonable-cause workflow turns scattered narratives into defensible, evidence-backed requests.
Discuss your firm’s authorization, transcript and CRM workflow in a 26T1 demo.