Severance pay does not count as 401(k) compensation. The IRS treats a severance check as a payment triggered by the end of your employment rather than pay for services you performed, and only pay for services can be deferred into a 401(k). A few final payments made shortly after your last day can still qualify, and severance income does count as compensation for IRA contributions even when the 401(k) door is closed.
Why Severance Fails the 401(k) Compensation Test
Every 401(k) plan limits elective deferrals to amounts that meet the definition of “compensation” under IRC Section 415(c)(3). That definition covers pay you receive for actually performing services for your employer. A severance payment doesn’t fit, because it isn’t a reward for work you did. It’s triggered by the termination itself.
Treasury regulations make the point directly: a cash or deferred arrangement only qualifies if elective deferrals are limited to amounts that are compensation within the meaning of Section 415(c)(3). An employee who has separated from service cannot make a deferral election on a payment made after severance unless it fits one of two narrow exceptions.1GovInfo. 26 CFR 1.401(k)-1 – Certain Cash or Deferred Arrangements The IRS has separately confirmed that when an employee receives severance payments, the employee “may not defer any to a 401(k) arrangement since the employee is no longer working for the employer.”2Internal Revenue Service. Chapter 3 Compensation
So a lump sum labeled “severance,” calculated on your years of service or any formula tied to the termination, cannot be deferred. It hits your taxable income for the year in full.
Post-Severance Payments That Can Still Qualify
Not everything that arrives after your last day is severance in the IRS’s eyes. Two categories of final payment represent compensation you already earned and can remain eligible for 401(k) deferrals.3GovInfo. 26 CFR 1.415(c)-2 – Compensation
The first is regular pay you would have received if you’d stayed employed: wages for work during your normal hours, overtime, shift differentials, commissions, and bonuses. A quarterly bonus based on work you already completed doesn’t lose eligibility just because the check arrives after your termination date.
The second is unused accrued leave. Payouts for vacation, sick days, or other paid time off you accumulated but never used can count, as long as you would have been able to use that leave if you’d remained employed.
Both categories share one condition: the payment has to arrive within a specific window.
The 2.5-Month Payment Window
For a post-severance payment to remain eligible for a 401(k) deferral, your employer must pay it by the later of two dates: two and a half months after your severance date, or the end of the plan’s limitation year (usually the calendar year) that includes your severance date.3GovInfo. 26 CFR 1.415(c)-2 – Compensation
In practice: if you leave on October 1, the 2.5-month mark is around December 15, but the end of the plan year (December 31) is later, so December 31 is your deadline. If you leave on November 15 instead, 2.5 months out lands around February 1 of the next year, which is later than December 31, so February 1 becomes the deadline. Any qualifying payment made inside that window can still support an elective deferral. Anything paid after it cannot, even if it’s for work you did months ago.
This trips people up when commissions or year-end bonus calculations take longer than expected. Slow payroll can close the window before the check lands, and there’s no way to fix it after the fact.
What Your Plan Document Can Do
Even when a payment clears the tax rules above, the plan document gets the last word. The plan has to specify which compensation definition it uses, and the IRS allows several options.4Internal Revenue Service. Compensation Definition in Safe Harbor 401(k) Plans
Common choices are W-2 wages (Box 1), wages subject to federal income tax withholding, or the broader Section 415 definition that includes nearly all taxable pay. A Section 415 plan casts the widest net; a W-2 plan with specific carve-outs can be narrower. Many sponsors deliberately choose restrictive definitions to simplify administration.
The document can also exclude specific payment types outright. If it says severance pay, leave payouts, or irregular payments are excluded from eligible compensation, your hands are tied regardless of what the tax code would otherwise allow. Before assuming any final payment qualifies for deferral, ask HR for the Summary Plan Description or the compensation definition in the plan document itself. This is where most assumptions fall apart.
Garden Leave and Salary Continuation
There’s one arrangement where severance-like payments remain fully eligible for 401(k) deferrals: you haven’t actually been terminated yet. Some employers put departing employees on “garden leave” or an extended notice period where you stay on the payroll, keep your benefits, and draw your regular salary without being expected to show up.
On garden leave you’re still an active employee. Plan participation hasn’t ended, and the payments you receive are regular wages to a current employee. You can generally keep making elective deferrals as you would in any other pay period, unless the plan document carves out this arrangement. The pivot point is your official termination date. After that date, subsequent payments become post-severance and fall under the stricter rules above.
If an employer offers you a choice between a lump-sum severance and a salary continuation arrangement, the 401(k) implications are worth weighing. Salary continuation that keeps you on the active roster preserves deferral eligibility in a way a post-termination lump sum does not.
Using Severance to Fund an IRA Instead
The rule that closes off the 401(k) doesn’t close off IRAs. The IRS defines IRA-eligible compensation as any amount properly shown in Box 1 of your W-2, reduced by any amount in Box 11 for nonqualified plans.5Internal Revenue Service. Publication 590-A, Contributions to Individual Retirement Arrangements (IRAs) Severance shows up in Box 1. There’s no separate “services rendered” requirement for IRAs the way there is for 401(k) deferrals.
So you can use severance to fund a Traditional IRA contribution (potentially deductible depending on income and workplace-plan coverage during the year) or a Roth IRA (not deductible, but grows tax-free). For 2026, the IRA contribution limit is $7,500, with an additional $1,100 catch-up if you’re 50 or older, bringing the total to $8,600.6Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
An IRA won’t absorb a $50,000 check the way a 401(k) deferral could. But if a deductible Traditional IRA contribution is available to you, it offsets part of the tax hit directly. If a spouse also has W-2 compensation, each of you can contribute to a separate IRA.
How Severance Is Taxed and Withheld
Whether or not any of it is eligible for deferral, severance is subject to federal income tax, Social Security tax, and Medicare tax.7Internal Revenue Service. Publication 15 (2026), (Circular E), Employers Tax Guide The IRS classifies severance as supplemental wages, so your employer uses different withholding math than on a regular paycheck.
For federal income tax, most employers withhold a flat 22% on supplemental wages up to $1 million in a calendar year. Supplemental wages above $1 million in a year are subject to mandatory 37% withholding.7Internal Revenue Service. Publication 15 (2026), (Circular E), Employers Tax Guide These rates were made permanent by legislation in 2025.
Social Security tax applies at 6.2% up to the annual wage base, and Medicare tax applies at 1.45% with no cap.8Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates If total wages for the year (including severance) exceed $200,000, your employer must also withhold an additional 0.9% Medicare tax on amounts above that threshold.9Internal Revenue Service.