Short version, Form 15103 lets you tell the IRS if you already filed, did not need to file, or the taxpayer is deceased. It is the fork in the road that keeps you out of the Substitute for Return pipeline.
This guide walks you through what to do, what to send, how the notice fits into the IRS process, and how to avoid unnecessary penalties and interest. All details in this guide reflect IRS pages and forms available as of January 14, 2026.
Key Takeaways
- Form 15103 is the IRS’s non‑filer response form that often arrives with CP59, CP515, CP516, or CP518 when IRS data shows no 1040 on file for a year.
- You can confirm you already filed, explain you were not required to file, or note the taxpayer is deceased, then attach proof. The IRS publishes the form, last revised June 2017.
- In many situations you can submit Form 15103 online through your IRS Online Account if you are only sending the form, not a return. Mail or fax also work.
- Answering prevents a Substitute for Return that uses only W‑2 and 1099 data and often overstates tax. If you get to a Notice of Deficiency, you typically have 90 days to petition Tax Court.
- Penalties can stack fast, up to 25% for failure to file, plus 0.5% per month for failure to pay, and interest compounding daily. Combined failure‑to‑file and failure‑to‑pay exposure can approach about 47.5% of unpaid tax over time. Current underpayment interest for Q1 2026 is 7%.
What Form 15103 Is and Why You Received It
Form 15103, titled Form 1040 Return Delinquency, is the IRS’s way to resolve a “no return on file” match for a year when third‑party data, think W‑2s and 1099s, suggests you should have filed. It usually rides along with a non‑filer notice such as CP59, CP515, CP516, or CP518. The notice asks you to either file the missing return or explain why there is no filing requirement.
Receiving Form 15103 does not mean the IRS already assessed tax. It means the clock has started for you to clarify your status before the IRS considers building a return for you using only third‑party records. Answering early preserves your deductions, credits, and filing status options.
A helpful change since 2024, if you are only submitting the form, not a tax return, you can often complete a mobile‑friendly Form 15103 inside your IRS Online Account. Otherwise, you can still mail or fax the paper form included with your notice. Follow the instructions on your specific letter.
Step‑By‑Step, How To Complete Form 15103
Take ten minutes to do this right. Clear, complete answers and the right attachment save weeks of back‑and‑forth.
- Identify yourself exactly as shown on the notice. Enter your full name, Social Security Number, mailing address, and a phone number with a good call time. The IRS uses these to match your response to the correct year.
- Pick the box that fits your situation, already filed, not required to file, or deceased. Fill in the tax year the notice references. Keep it to the year on the letter.
- Write a short explanation. State key facts and dates, for example, filed on April 10, 2025 by mail, or below the filing threshold for 2023 with total income of X. Keep it specific, not long.
- Attach proof that closes the loop. If you already filed, include a signed and dated copy of the return, or the signed page 2 of Form 1040, or e‑file acceptance, then note the filing date and method in the explanation area.
- If you were not required to file, include details that matter, filing status, total income, and the reason, for example, income under threshold, nonresident with no U.S. filing requirement, or dependent, plus any confirming documents you have.
- For a deceased taxpayer, include the date of death and, if filed, the estate’s Form 1041 and EIN. If you have a death certificate, include a copy.
- Sign and date the form under penalties of perjury. If you are only sending the form, you may be able to submit it online through your IRS Online Account. If you are sending a tax return with it, mail as instructed on your notice. Keep copies of everything.
Pro Tip For Firms
If you manage this for clients, standardize a one‑page checklist, ID match, year verified, status selected, proof attached, signature present, and create a naming convention for scans. It speeds partner review and avoids rework. If your internal team is stretched during peaks, a structured offshore review step can help clear these notices without clogging partner time. That is the kind of operational discipline Accountably builds for firms, SOPs, structured workpapers, and defined SLAs, so small tasks do not become bottlenecks.
If You Already Filed Or You Do Not Need To File, What To Send
Match your response to your situation, then add the proof the IRS can verify.
- If you already filed, check “already filed,” list the year, add the filing date and method, and attach a signed copy of the return or the signed signature page. Include your contact details, sign and date Form 15103, then mail as directed. If you are only sending Form 15103 to say you already filed, you can often submit it through your IRS Online Account instead of mailing or faxing.
- If you were not required to file, check “not required to file,” list the year, state filing status and total income, then give a short reason with support if available. Examples include income below threshold or nonresident status. Sign and date.
- If the taxpayer is deceased, check “deceased,” note the date of death, and provide estate details if a Form 1041 was filed. Include a copy of the death certificate when available.
Keep your tone factual and brief. The reviewer is matching identifiers and dates, not evaluating a narrative.
If You Still Need To File Your Past‑Due Return
You can resolve the form and the missing return in one packet.
- Complete Form 15103 with your info. Check the box that applies, usually “I will file” if you are enclosing a past‑due return. Sign and date the form.
- Prepare the specific year’s Form 1040 and schedules. Sign the return, then attach it behind Form 15103 and mail to the address on your notice.
- Electronic filing rules, the IRS accepts prior‑year e‑files for the two most recent prior years. If your missing year falls outside that window, you will likely paper‑file.
If cash flow is tight, do not pause your filing. File first to stop the worst penalties, then explore payment plans or other options.
Where Form 15103 Fits In The IRS Process
Form 15103 arrives with non‑filer notices that escalate if you stay silent.
- CP59 or CP515, initial contact and reminder that no 1040 is on file. The IRS asks you to file or explain. Form 15103 is the tool to respond.
- CP516, follow‑up stating the IRS still has no record. You can submit only the form online through your IRS Online Account or mail or fax it, or you can send the form together with the signed return.
- CP518, final reminder. If you ignore it, the case can move toward a Substitute for Return and a Notice of Deficiency.
Non‑Filer Notices Timeline
| Notice | What it means | Your fastest move |
| CP59 or CP515 | IRS has no 1040 on file for the year | File the return or send Form 15103 with proof |
| CP516 | IRS still shows no return | Submit Form 15103 online through your IRS Online Account if form only, or mail with your signed return |
| CP518 | Final reminder | Send your filed return copy with Form 15103 right away to avoid SFR and deficiency |
Sources, see the IRS “Understanding your notice” pages for CP59, CP515, CP516, and CP518.
The Substitute For Return Risk
If you do nothing, the IRS may prepare a Substitute for Return based only on third‑party reports. That return often excludes your deductions and credits, and it may default to a less favorable filing status. The next step is a Notice of Deficiency, commonly CP3219N or CP3219A, which gives you 90 days to file a petition in U.S. Tax Court. Miss that window, and the assessment finalizes.
If you receive a deficiency notice, you can still file your actual return and provide documentation. The IRS explains how to respond, and it will not extend the 90‑day petition deadline while it reviews your materials, so move quickly.
The best way to avoid the SFR pipeline is simple, file the missing return or send Form 15103 with proof that you already filed.
For CPA Firms, A Quick Operations Tip
If your team handles batches of CP59 or CP516 notices, build a light SLA, 48‑hour triage, 7‑day client follow up, 14‑day file complete. Use a single folder template, notice, Form 15103, proof, and return, with standardized filenames. This avoids partner review loops and keeps deadlines on track. If peak season makes this slip, a disciplined offshore delivery step with SOPs and multi‑layer review can stabilize the queue, which is the operating model Accountably implements for firms that want capacity without chaos.
Deadlines, Penalties, And Interest
Form 15103 itself does not carry a statute, but the notice that arrives with it does. Treat that window as your deadline. If you ignore the letters, penalties and interest continue and your case can escalate to a deficiency notice and collections.
- Failure‑to‑file penalty, 5% per month, up to 25% of unpaid tax. If both failure‑to‑file and failure‑to‑pay apply in the same month, the failure‑to‑file rate is reduced by the failure‑to‑pay amount for that month.
- Failure‑to‑pay penalty, 0.5% per month, up to 25%. Over time, combined exposure from these two penalties can approach about 47.5% of unpaid tax, plus interest.
- Minimum late‑filing penalty for very late returns, for returns due after December 31, 2025, the minimum is $525 or 100% of the unpaid tax, whichever is less.
- Interest, the IRS underpayment rate for Q1 2026 is 7%, compounded daily. Interest accrues on tax and on many penalties until paid in full.
If a disaster or other event delayed you, some deadlines may shift, however, interest and some penalties can still apply for periods outside the relief window. Check your notice or the IRS disaster relief page for your county and dates.
Common Mistakes That Slow Everything Down
- Saying “already filed” without attaching a signed copy, or at least e‑file proof. The IRS keeps treating the year as open.
- Leaving out the signature and date on Form 15103 or on the attached return.
- Using the wrong tax year or mismatched SSN and address compared with the notice.
- Claiming “not required to file” with no income totals or explanation.
- Mailing only Form 15103 when you still need to file the return, which delays resolution.
DIY Or Call A Pro
You can usually handle a single‑year CP59 or CP516 when your income is simple, mostly W‑2s or straightforward 1099s, and you can attach a signed return or proof of filing. If you have multiple unfiled years, missing records, significant self‑employment income, or a prior SFR, consider professional help. It saves time and reduces risk once notices start to stack.
If you lead a CPA or EA firm and your internal team is buried in notice work, consider an operational fix, not just headcount. This is where Accountably works with firms as a U.S.‑led offshore partner, structured SOPs, standardized workpapers, SLAs, and layered review that keep partners out of review loops and work on time. Use it when notice volumes spike and you want predictable turnaround with documentation discipline.
Frequently Asked Questions
What is Form 15103 used for?
Form 15103 lets you tell the IRS whether you already filed, were not required to file, or the taxpayer is deceased for a specific year. You can attach a signed copy of the return or supporting documents. The paper form is still the June 2017 version.
Can I submit Form 15103 online?
In many situations, yes. If you are only sending Form 15103 to say you already filed or were not required to file, you can often submit a mobile‑friendly version through your IRS Online Account. If you are sending a tax return with it, mail to the address on your notice.
What is the IRS “one‑time forgiveness” people mention?
That is First Time Abate. If you have a clean compliance history for the prior three years, the IRS may remove certain penalties one time. If you do not qualify, you can still request reasonable cause relief with documentation.
How do I ask the IRS to remove penalties and interest?
Ask for penalty relief, either First Time Abate or reasonable cause, and be ready with dates and documents. The IRS can remove related interest when it removes a penalty, however it does not remove interest simply because paying is hard.
What if I cannot pay the full balance?
File the return anyway to stop the biggest penalties, then apply for a payment plan with the IRS. Interest continues until paid in full, so earlier filing and partial payments reduce the total cost.
Conclusion
You have a clear path. If you already filed, send Form 15103 with a signed copy or submit the mobile‑friendly form through your IRS Online Account. If you did not file, prepare and sign the missing return and mail it with Form 15103. Watch your 90‑day window if a deficiency notice arrives, and move quickly to keep options open.