How Do You Get an Extension for Form 5500-EZ? (w/Examples) + FAQs

Quick Answer: For the 2025 plan year, you get an extension on Form 5500-EZ by filing Form 5558 on or before the normal due date. This grants a one-time extension of up to 2½ months, moving a July 31, 2026 deadline to October 15, 2026.

If you run a solo 401(k) or another owner-only retirement plan, you may already know that Form 5500-EZ is due by the last day of the 7th month after your plan year ends. For a calendar-year plan, that is July 31. When that date is bearing down and your numbers are not ready, missing it triggers a penalty of $250 per day, up to $150,000 per plan year, under Code section 6652(e) — so an extension is not a luxury, it is protection.

The good news is that the IRS gives you a clean, no-questions-asked way to buy more time. There is no fee, no penalty for asking, and the IRS does not even require a reason. You simply file the right form before your deadline, keep a copy, and you have until October 15 (for a calendar-year plan) to finish. This guide walks you through every path to that extension, with real dollar examples and named scenarios.

This article reflects federal rules as of June 2026 and covers the 2025 plan year (filed in 2026). Form 5500-EZ is a federal-only filing handled by the IRS, so there is no separate state extension. Tax law changes — confirm current figures before you file. This is educational information, not a substitute for advice from a licensed CPA, ERISA attorney, or third-party administrator (TPA) for your specific plan.

Here is what you will learn:

📝 The exact form to file for an extension and the deadline that cannot be missed.
⏰ How to get an automatic extension without filing any extension form at all.
💸 What the late-filing penalty really costs — and the relief program that caps it.
🧮 Three fully worked dollar examples so you can copy the math for your own plan.
⚠️ The seven mistakes that quietly turn a simple extension into a five-figure problem.

What Form 5500-EZ Is

Form 5500-EZ is the annual return for a one-participant retirement plan. A one-participant plan, as defined in the Form 5500-EZ instructions, is a plan that covers only a business owner (or an owner and spouse), or only partners (and their spouses) in a business partnership. The most common example is a solo 401(k), but it also covers owner-only defined benefit plans, money purchase plans, and profit-sharing plans.

You must file Form 5500-EZ once your plan’s total assets exceed $250,000 at the end of the plan year, or in the plan’s final year when all assets are distributed. This threshold is per employer and combines all one-participant plans the same employer maintains. Below $250,000 and not terminating, you generally do not file at all.

The return is filed under Code section 6058(a), not under Title I of ERISA, which is why owner-only plans use the “EZ” version instead of the full Form 5500. That distinction matters for extensions, because it controls which relief programs apply to you. A late or missed 5500-EZ is treated as a federal information-return failure, and the penalty math is steep.

Why the deadline is strict

The filing deadline is the last day of the 7th calendar month after the plan year ends. For a calendar-year plan ending December 31, 2025, that is July 31, 2026. If the due date lands on a Saturday, Sunday, or legal holiday, you may file on the next business day.

The consequence of blowing past that date without an extension is immediate and mechanical. The IRS does not need to prove harm — the $250-per-day clock simply starts. What you should do: mark the deadline the moment your plan year ends, and decide by early July whether you need more time.

The Three Ways To Get an Extension

There is not one extension path — there are three, and choosing the right one matters. Each has its own form (or no form), its own conditions, and its own box to check on the eventual Form 5500-EZ. Picking the wrong one, or assuming one applies when it does not, can leave you exposed to the full penalty.

The three routes are: filing Form 5558, riding your business tax-return extension automatically, or relying on a special IRS-announced extension. Most solo 401(k) owners use Form 5558 because it is simple and certain. The automatic route is convenient but has strict conditions, and the special route only appears during disasters or combat-zone service.

Below, each route gets a full breakdown: what it is, what happens if you misuse it, a real example, the common misconception, and your next step.

Route 1 — File Form 5558

Form 5558, the Application for Extension of Time To File Certain Employee Plan Returns, is the standard extension request. Filing it on or before the normal due date gives you a one-time extension of up to 2½ months. For a calendar-year plan, that moves July 31, 2026 to October 15, 2026.

The consequence of getting the timing wrong is total: Form 5558 must be filed on or before the normal due date, with no extensions counted. File it even one day late and it is void — you get no extension, and the daily penalty runs from the original date. You do not attach Form 5558 to the 5500-EZ; instead you keep a copy with your plan records and check the “Form 5558” box in Part I, line B of the return.

A common misconception is that the IRS must approve the request. It does not — Form 5558 for the 5500 series is automatically granted when filed on time, so you should never wait for a confirmation letter. What you should do: file Form 5558 by your normal due date, retain a stamped or dated copy, and then check line B’s “Form 5558” box when you file the return.

Route 2 — The automatic extension

If your plan year matches your business tax year, you may get an automatic extension to your business return’s extended due date — with no Form 5558 at all. Per the Form 5500-EZ instructions, three conditions must all be met: the plan year and the employer’s tax year are the same; the employer has a valid extension of its income tax return to a date later than the normal 5500-EZ due date; and a copy of that income-tax extension is kept with the plan’s records.

The consequence of misreading this is subtle. If your tax-return extension date is earlier than the 5500-EZ due date, this route gives you nothing. And an automatic extension obtained this way cannot be stretched further by filing a Form 5558 afterward. A common misconception is that any business extension automatically covers the plan — it only does so when all three conditions line up and the dates work in your favor.

What you should do: if you plan to use this route, check the “automatic extension” box in Part I, line B, keep your Form 7004 or Form 4868 extension copy, and confirm the extended tax date is later than July 31.

Route 3 — Special IRS-announced extensions

The IRS sometimes announces special extensions for federally declared disasters or for service in a combat zone. These are not requested on a form — they apply automatically to taxpayers in the covered area or situation, and the IRS publishes the deadline and the authority.

If you rely on one, check the “special extension” box on Part I, line B and enter a short description of the announced authority. The consequence of claiming this incorrectly — when you are not actually in a covered zone or period — is that the extension does not apply and the penalty runs. What you should do: confirm your relief on the IRS disaster relief page before relying on it, and save the IRS notice with your records.

Which Situation Applies To You?

The right path depends on a few simple facts about your plan and business. Use the branches below to find yours, then read the matching route above.

If you simply want guaranteed extra time and dislike uncertainty, file Form 5558 (Route 1) — it is the cleanest path for most solo 401(k) owners.
If your plan year and business tax year match and you have already extended your business return to a date past July 31, you may already have an automatic extension (Route 2) with no extra filing.
If you live or operate in a federally declared disaster area, or you are serving in a combat zone, check for a special extension (Route 3) before doing anything else.
If your plan’s assets are at or below $250,000 at year-end and it is not the final year, you likely do not have to file at all, so no extension is needed.
If you have already missed the deadline, skip extensions entirely and go straight to the Late Filer Penalty Relief Program described below.

How To Fill Out and File Form 5558

Form 5558 is short, but precision matters because a single mismatch can void it. The form asks for the filer/plan sponsor name, the plan name, the three-digit plan number, the employer identification number (EIN), and the plan year ending date.

Line A asks for the “Name of filer, plan administrator, or plan sponsor.” For a one-participant plan, this is generally the same as the employer name. You enter the plan name and plan number exactly as they appear on your Form 5500-EZ — a mismatch here is one of the most common reasons an extension is questioned later.

You file Form 5558 by mailing the paper form to the IRS in Ogden, Utah, or, effective January 1, 2025, you may file it electronically through EFAST2. Do not list more than three plans on a single Form 5558, and do not attach extra lists. Keep a dated copy with your plan records — you will not attach it to the return.

Step-by-step

Confirm your normal due date (July 31, 2026 for a calendar-year 2025 plan).
Enter the sponsor/employer name, EIN, plan name, and plan number exactly as on the 5500-EZ.
Enter the plan year ending date.
File the form — paper to Ogden, UT, or electronically via EFAST2 — on or before the due date.
Save a dated copy with your plan records.
When you file the 5500-EZ later, check the “Form 5558” box in Part I, line B.

The consequence of skipping step 5 is real: if the IRS ever questions the late return, your retained copy of the timely Form 5558 is your proof. Without it, you may have to argue the extension existed at all.

Worked Examples With Real Dollars

Numbers make the rules concrete. Each example below uses real figures so you can copy the math for your own plan, anchored to the 2025 plan year filed in 2026.

Example 1 — Maria files Form 5558 on time

Maria runs a one-person design studio with a solo 401(k) that held $310,000 at year-end 2025, so she must file Form 5500-EZ. Her plan year is the calendar year, making her normal due date July 31, 2026. Her bookkeeper is behind, so on July 20, 2026 she files Form 5558.

Her extension is automatically granted, moving her deadline to October 15, 2026. She files the 5500-EZ on October 2, 2026, checks the “Form 5558” box, and owes $0 in penalties. The 2½-month cushion cost her nothing.

Example 2 — David misses the date by filing late

David also has a calendar-year solo 401(k) above the threshold. He forgets the deadline and files Form 5558 on August 5, 2026 — six days after July 31. Because Form 5558 must be filed on or before the normal due date, his request is void.

He finally files the 5500-EZ on September 30, 2026 — 61 days late. At $250 per day, his exposure is 61 × $250 = $15,250. Had he filed Form 5558 by July 31, that entire amount would have been zero.

Example 3 — Priya uses the automatic extension

Priya’s consulting LLC files Form 7004 to extend its business return to September 15, 2026, and her plan year matches her tax year. Because that date is later than July 31, 2026 and she keeps a copy of the 7004, she qualifies for the automatic extension — no Form 5558 needed.

She files the 5500-EZ on September 10, 2026 and checks the “automatic extension” box. Her cost is $0. Note: she could not have then filed a Form 5558 to push past September 15, because that route closes once the automatic extension applies.

Three Common Extension Scenarios

Extension situation	What happens to your deadline
You file Form 5558 by July 31, 2026	Deadline moves to October 15, 2026; extension granted automatically with no IRS approval needed.
Your business tax extension runs past July 31 and your plan year matches	You get an automatic 5500-EZ extension to that later date with no Form 5558, if you keep the tax-extension copy.
You file Form 5558 after July 31, 2026	The request is void; you have no extension and the $250-per-day penalty runs from July 31.

What Happens If You Miss the Deadline

If you blow the deadline without a valid extension, the Code section 6652(e) penalty applies: $250 per day, capped at $150,000 per plan year. The clock runs from the original due date until you actually file, which is why a 60-day delay can cost over $15,000.

The lifeline is the IRS Late Filer Penalty Relief Program under Revenue Procedure 2015-32. It lets eligible one-participant and certain foreign plans clear delinquent 5500-EZ filings for a reduced, capped penalty instead of the full daily amount. This program exists precisely because so many solo plan owners simply did not know they had to file.

To use it, you must submit a complete paper Form 5500-EZ for each delinquent year (it cannot be e-filed through EFAST2), attach Form 14704 to the front of the oldest delinquent return, and mark the relief language. On the 2025 form you check box D; on older forms you print in red letters above the title: “Delinquent Return Submitted under Rev. Proc. 2015-32, Eligible for Penalty Relief.”

The consequence of ignoring this program is severe — once the IRS assesses the full $250-per-day penalty, the program is no longer available to you. What you should do: if you discover a missed year, file under Rev. Proc. 2015-32 before the IRS contacts you.

Mistakes To Avoid

Filing Form 5558 even one day late. The request is void, and the daily penalty runs from the original due date as if you never filed.
Attaching Form 5558 to the 5500-EZ. You keep the copy with plan records instead; attaching it can cause processing confusion.
Forgetting to check the line B box. If you do not check “Form 5558,” “automatic extension,” or “special extension,” the IRS may not see that you extended.
Assuming a business extension always covers the plan. The automatic route only works when the plan year matches the tax year and the extended date is later than July 31.
Trying to stack extensions. You cannot use the automatic extension and then file Form 5558 to push the deadline further.
Not retaining proof. Without a dated copy of Form 5558 or your business extension, you cannot defend the extension if questioned.
Listing more than three plans on one Form 5558. The IRS instructs filers not to exceed three plans or attach lists, which can invalidate the request.
Ignoring the $250,000 threshold rule. Filing late because you misjudged whether you had to file at all still triggers the penalty.

Do’s and Don’ts

Do file Form 5558 by the normal due date — early is safer than exact.
Do keep a dated copy of every extension document with your plan records, because that is your only proof.
Do confirm your plan year and tax year match before relying on the automatic route, since a mismatch voids it.
Do check the correct line B box on the 5500-EZ, so the IRS links your extension to your return.
Do use the Rev. Proc. 2015-32 program immediately if you are already late, because it caps an otherwise massive penalty.
Don’t wait for an IRS approval letter for Form 5558 — the extension is automatic when timely.
Don’t e-file a delinquent return under the relief program, because it must be filed on paper.
Don’t assume a no-income-tax state matters here — the 5500-EZ is federal only.
Don’t stack the automatic extension with a later Form 5558, which is not allowed.
Don’t guess on your plan number or EIN, since a mismatch can stall the whole extension.

Pros and Cons of Filing Form 5558

Pro: It is free — there is no fee to request the extension.
Pro: It is automatic — no IRS approval or reason is required.
Pro: It gives a solid 2½ months, enough to gather year-end valuations.
Pro: It can now be filed electronically through EFAST2 as of 2025, not only on paper.
Pro: It creates a clean paper trail that protects you if the return is questioned.
Con: It must be filed on or before the due date — there is zero margin for lateness.
Con: It only buys 2½ months; it is not an indefinite reprieve.
Con: It does not extend the time to fund anything — it only extends the filing.
Con: A clerical mismatch (name, EIN, plan number) can undermine it.
Con: It cannot be stacked on top of an automatic extension for more time.

Costs and Timing

There is no IRS fee to file Form 5558, whether on paper or through EFAST2. If you prepare your own solo 401(k) return, your only cost is your time — the IRS estimates a few hours total for the 5500-EZ itself. If you hire a TPA or CPA, a 5500-EZ with an extension commonly runs from roughly $150 to $500 depending on plan complexity, though fees vary by provider.

Timing is the part that bites. The extension must be requested before the normal due date, and it buys exactly 2½ months — moving a July 31 deadline to October 15 for a calendar-year plan. There is no second extension beyond that.

When To Call a Professional

A solo 401(k) with simple assets and a clear year-end balance is often a do-it-yourself filing. But some situations genuinely warrant a CPA, ERISA attorney, or a TPA. These professionals help with defined benefit plans requiring an actuary’s Schedule SB, plan terminations, multiple stacked plans, or a delinquent-filing cleanup under Rev. Proc. 2015-32.

The consequence of going it alone in a complex case can be a five-figure penalty or a botched relief filing. If you are unsure whether you crossed the $250,000 threshold, or you have several missed years, the cost of an hour of professional advice is small next to a $150,000 maximum penalty.

What To Do Next

Confirm your normal due date — July 31, 2026 for a calendar-year 2025 plan.
Decide your route: Form 5558, automatic (if your tax-return extension runs later), or special (disaster/combat zone).
If using Form 5558, file it — paper to Ogden, UT, or via EFAST2 — on or before the due date.
Gather year-end plan asset values, contributions, and any participant-loan figures.
Keep a dated copy of your extension document with your plan records.
When you file the 5500-EZ, check the correct box in Part I, line B.
If you are already late, file under Rev. Proc. 2015-32 with Form 14704 before the IRS contacts you.

FAQs

What form do I use to extend Form 5500-EZ? Form 5558. Filing the Application for Extension on or before the normal due date grants a one-time extension of up to 2½ months. Keep a copy and check the “Form 5558” box on the return.

How long is the Form 5500-EZ extension? Up to 2½ months. For a calendar-year 2025 plan, this moves the July 31, 2026 deadline to October 15, 2026. There is no further extension beyond that date.

Does the IRS have to approve Form 5558? No. For the Form 5500 series, a timely filed Form 5558 is automatically granted. You should not wait for any approval letter — just retain your dated copy as proof.

Is there a fee to file Form 5558? No. The IRS charges no fee to request the extension, whether you file on paper to Ogden, Utah, or electronically through the EFAST2 system as of 2025.

Can I get an extension without filing Form 5558? Yes. If your plan year matches your business tax year and you extended your business income tax return to a date later than July 31, you get an automatic extension — no Form 5558 needed.

When is the Form 5500-EZ extension request due? On or before the normal due date. For a calendar-year plan that is July 31, 2026. A Form 5558 filed even one day late is void, and the penalty runs from the original date.

What is the penalty for filing Form 5500-EZ late? $250 per day. Under Code section 6652(e), the penalty caps at $150,000 per plan year. A 60-day delay, for example, would expose you to roughly $15,000.

Can I fix a missed Form 5500-EZ filing? Yes. The IRS Late Filer Penalty Relief Program under Revenue Procedure 2015-32 lets eligible plans clear delinquent returns for a reduced, capped penalty if you file on paper with Form 14704 attached.

Do I attach Form 5558 to my Form 5500-EZ? No. You keep the completed Form 5558 with your plan records and check the “Form 5558” box in Part I, line B. Do not attach it to the return.

Can I file Form 5558 electronically? Yes. Effective January 1, 2025, Form 5558 can be filed electronically through EFAST2, in addition to the traditional paper filing mailed to the IRS in Ogden, Utah.

Do I even have to file Form 5500-EZ? Only above $250,000. You must file once your one-participant plan’s total assets exceed $250,000 at year-end, or in the plan’s final year. Below that, and not terminating, you generally do not file.

Can I stack two extensions for more time? No. If you rely on the automatic extension tied to your business tax return, you cannot then file Form 5558 to push the deadline even further past that date.

Is there a state extension for Form 5500-EZ? No. Form 5500-EZ is a federal-only filing handled by the IRS. There is no separate state return or state extension associated with it.

This article reflects federal rules as of June 2026 and covers the 2025 plan year. Word count: approximately 2,950.

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