IRS Form 5329 for a Missed RMD: Penalty, Part IX, and Waiver

If you missed a required minimum distribution, IRS Form 5329 is where you report the shortfall, calculate the excise tax, and, if you have a reasonable explanation, ask the IRS to waive the penalty entirely. The tax is 25% of the amount you should have withdrawn but didn’t, dropping to 10% if you take the missed distribution within a correction window. Everything happens in Part IX of the form.

What the Penalty Actually Costs Now

The SECURE 2.0 Act, enacted in December 2022, cut the excise tax on missed RMDs from 50% to 25% of the shortfall for any taxable year beginning after December 29, 2022.¹ Older articles still quote the 50% figure. Ignore them. A $20,000 miss now costs $5,000 rather than $10,000.

The rate drops further to 10% if you withdraw the missed amount during the correction window. That same $20,000 miss costs $2,000 if you catch it in time. The window runs from the missed deadline until the earliest of three events: the IRS mails you a notice of deficiency, the IRS formally assesses the tax, or the last day of the second taxable year after the year the RMD was due. For most people the third date is what governs. Miss a 2025 RMD and you generally have until December 31, 2027 to take the distribution at the reduced rate.¹

To claim the 10% rate you must do both things: take the missed distribution and file Form 5329 during the correction window. Withdrawing the money without filing doesn’t get you there.

Figuring the Shortfall

Your shortfall is the required amount minus whatever you actually withdrew by the deadline. If your RMD was $25,000 and you took $10,000, the shortfall is $15,000. If you withdrew nothing, the full RMD is the shortfall. The excise tax applies to that number.

Use the life expectancy factor for your age in the year the RMD was due, not the year you’re filing. Filing in 2026 for a 2025 miss? Use your 2025 age.

Filling Out Part IX Line by Line

The missed-RMD penalty lives in Part IX of Form 5329, “Additional Tax on Excess Accumulation in Qualified Retirement Plans (Including IRAs).”² Part IX splits the calculation into two tracks. The “a” lines handle shortfalls you corrected inside the correction window (10% rate). The “b” lines handle everything else (25% rate).

Line 52a: required minimum distribution from plans where you already took the full missed amount inside the correction window.
Line 52b: required minimum distribution from all other plans.
Line 53a: amount actually distributed from the correction-window plans.
Line 53b: amount actually distributed from all other plans.
Line 54a: line 52a minus line 53a, multiplied by 10%.
Line 54b: line 52b minus line 53b, multiplied by 25%.
Line 55: lines 54a and 54b added together. This total flows to Schedule 2 (Form 1040), line 8.³

If you corrected the entire shortfall in time, the “b” track is zero and you only owe 10%. If you didn’t correct any of it, the “a” track is zero and you pay 25% on the full amount.

Use the version of Form 5329 that matches the year of the missed RMD, not the current-year form. Missed a 2024 distribution and filing now? Use the 2024 form.²

Requesting a Waiver on the Form

The IRS can waive some or all of the excise tax if the shortfall was due to reasonable error and you’ve taken steps to correct it.⁴ You don’t skip the form and hope no one notices. You file the form, show the calculation, and formally request the waiver on it.

The mechanics live on lines 54a and 54b, not on line 55 as some older guides claim:

Complete lines 52a/52b and 53a/53b with the actual required amounts and distributions, exactly as if no waiver were being requested.
On the dotted line next to line 54a or 54b, write “RC” followed by the shortfall amount you want waived, in parentheses. Subtract that amount from the total shortfall and enter the reduced figure on line 54a or 54b.
Compute line 55 based on the adjusted figures. If you’re asking that the whole penalty be waived, lines 54a/54b and line 55 will all be zero.⁴

“RC” is short for reasonable cause. That notation is what tells the IRS you’re claiming a waiver rather than fumbling the arithmetic.

The Explanation Letter

Attach a signed letter with the form. Keep it factual and chronological. The IRS is looking for three things: what went wrong, why it was a reasonable error or outside your control, and what you did to fix it (ideally, that you’ve already taken the missed distribution).

Reasons the IRS tends to accept include errors by a financial institution, such as a standing distribution order that wasn’t executed, serious illness or hospitalization, and incorrect advice from a tax professional. For a medical claim, attach hospital records or a doctor’s letter with dates.⁵

The IRS reviews these individually. If granted, you’ll get a notice and owe nothing beyond the ordinary income tax on the distribution itself. If denied, you’ll get a notice of the additional tax owed. In practice the IRS grants waivers fairly liberally when the taxpayer has already taken the corrective distribution and offers a clear explanation. “I forgot,” without more, is a weaker showing than a documented institutional error.

Where and How to File

If you’re filing your Form 1040 for the same year you missed the RMD, attach Form 5329 to the return. The line 55 amount flows to Schedule 2, line 8, and into your total tax. Include the waiver letter as an attachment.²

If you’ve already filed that year’s return, or you aren’t required to file one, Form 5329 goes in by itself. Mail it to the IRS service center where you would normally send your Form 1040; the address for your state is in the Form 5329 instructions for the applicable year.² A standalone Form 5329 cannot be filed electronically; it has to be paper.⁴ Send it certified mail with return receipt so you have proof of the filing date.

Missed RMDs Across Multiple Years

Each missed year needs its own Form 5329, on that year’s version of the form.² Each has its own shortfall calculation based on that year’s ending balance and life expectancy factor, and, if you’re requesting a waiver, its own explanation letter. You can put them all in one envelope.

Why You Should File Even If You’re Sure a Waiver Will Be Granted

Some people who miss an RMD and plan to request a waiver decide to skip the form and take their chances. That’s a real mistake, because of how the statute of limitations works.

The IRS normally has three years from the filing of a return to assess additional tax. For excise taxes under Section 4974, that stretches to six years from the filing of your income tax return for the year the RMD was missed.⁶ If you never file Form 5329, the clock never starts. The IRS can come back years later. Filing the form with “RC” and a zero tax amount starts the limitations period, preserves the record if the waiver is granted, and caps your downside if it isn’t.

A Note for Inherited-Account Beneficiaries

The same excise tax and the same Form 5329 apply to beneficiaries who miss required distributions from inherited traditional IRAs, Roth IRAs, or employer plans. Under the SECURE Act’s 10-year rule, most non-spouse beneficiaries must empty an inherited account within ten years of the owner’s death, and when the original owner died after reaching RMD age, annual distributions are generally required during that ten-year period.⁷ One aggregation rule matters when you calculate the shortfall: distributions from IRAs inherited from the same person can be combined to meet the total RMD, but distributions from IRAs inherited from different people cannot.² The Part IX mechanics are otherwise the same.

1
Office of the Law Revision Counsel. 26 USC 4974 – Excise Tax on Certain Accumulations in Qualified Retirement Plans
2
Internal Revenue Service. Instructions for Form 5329 (2025)
3
IRS. Form 5329 (Draft)
4
IRS. Instructions for Form 5329 (2025)
5
Internal Revenue Service. Penalty Relief for Reasonable Cause
6
Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
7
Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs