Inherited a 401(k)? Cash Out vs Roll to Inherited IRA

Marcus, 38, single, lives in Georgia and earns a $90,000 salary. His father died in March 2026 and named Marcus the sole beneficiary of a $300,000 traditional 401(k). The plan administrator sends him a packet with one tempting box: “Request lump-sum distribution.” If Marcus checks it, the entire $300,000 becomes ordinary income in 2026, stacked on his salary — pushing his top dollars into the 35% federal bracket and adding roughly $89,000 in federal tax plus about $16,200 in Georgia tax (5.39% flat). If instead he transfers the balance into an inherited IRA and withdraws roughly $37,500 a year over 8 years, most of that income stays in the 22%–24% brackets — cutting his federal tax on this money by an estimated $22,000. Same inheritance, same penalty-free treatment, drastically different bill. The lever is timing.

The one rule that makes this simple: no penalty, ever

Start with the fear that drives bad decisions. Many people assume that touching a 401(k) before age 59½ means a 10% penalty. For your own account, that is true. For an inherited account, it is not.

Under IRC §72(t)(2)(A)(ii), distributions made to a beneficiary on or after the death of the account owner are exempt from the 10% early-withdrawal penalty at any age. Marcus is 38 — it does not matter. He could withdraw the full $300,000 tomorrow and owe $0 in penalty. So the cash-out-versus-roll decision is not about penalties. It is purely about how many tax brackets you light up and in which years. Once you internalize that, the math gets clean.

Cash out now: the entire balance is ordinary income in one year

A traditional (pre-tax) 401(k) was funded with money that was never taxed. The IRS collects on the way out. When a beneficiary cashes out, every dollar of the pre-tax balance is ordinary income in the year received — taxed on the 2026 brackets, not at capital-gains rates. There is no step-up in basis for a retirement account (step-up under IRC §1014 applies to taxable assets like a brokerage account or a house — not to a 401(k) or IRA).

For Marcus, cashing out means $90,000 salary + $300,000 distribution = $390,000 of taxable income before deductions. After the 2026 single standard deduction of $15,750, his taxable income is about $374,250. Watch what the inherited money does as it stacks:

Run the brackets and the lump-sum cash-out costs Marcus roughly $89,000 in federal income tax on the inherited portion alone (about $124,000 of it taxed at the top 35% rate), before Georgia’s 5.39% flat tax adds about $16,200 more. The 10% penalty he was worried about? $0. The bracket spike he wasn’t worried about did all the damage.

Cashing out makes sense in a narrow set of cases: the balance is small (say, under $25,000, where it barely moves your bracket), you have a low-income year (between jobs, in school, retired before Social Security), or you need the cash for an emergency that would otherwise cost more than the tax. For a six-figure balance landing on top of a normal salary, it is almost always the expensive choice.

Roll to an inherited IRA: spread the tax across the 10-year window

The alternative is a trustee-to-trustee transfer into an inherited IRA (also called a beneficiary IRA). The money moves directly from the 401(k) plan to the inherited IRA without passing through Marcus’s hands. Nothing is taxed at the moment of transfer. He then controls the withdrawal schedule, subject to the 10-year drain rule.

The SECURE Act 10-year rule

Because Marcus is a non-spouse who is not within 10 years of his father’s age (he is a “non-eligible designated beneficiary”), the SECURE Act’s 10-year rule applies under IRC §401(a)(9)(H). He must empty the inherited IRA by December 31, 2036 — the 10th year after the 2026 death. Within that window he has two scenarios:

• Decedent had NOT yet started RMDs (died before his required beginning date): no annual withdrawal is required in years 1–9. Marcus can take $0 for nine years and everything in year 10 — or smooth it. He has full flexibility on timing as long as the account is empty by year 10.
• Decedent HAD started RMDs (was 73+ and past his required beginning date): under the IRS’s 2024 final regulations (26 CFR §1.401(a)(9)-5), Marcus must take an annual RMD in years 1–9 based on his own life expectancy and empty the account by year 10. The IRS waived enforcement of these year-1–9 RMDs for 2021–2024, but they are now in force.

Either way, the smart play is to withdraw a roughly level amount each year so the income never spikes into a high bracket. For Marcus, splitting $300,000 across 8 years is about $37,500/year. Added to his $90,000 salary, his gross income is about $127,500 — roughly $111,750 of taxable income after the $15,750 single standard deduction, topping out in the 24% bracket and never touching 32% or 35%.

Side-by-side: lump sum vs 8-year smoothing on $300,000

The roll-and-smooth approach not only cuts the tax — it leaves the remaining balance growing tax-deferred for up to a decade. That extra compounding is a second, quieter win on top of the bracket savings.

The Roth 401(k) portion: drain it last

If part of your father’s 401(k) was a Roth 401(k), the rules flip in your favor. A qualified Roth distribution is 100% income-tax-free under IRC §402A, provided the Roth account was open for at least 5 years before death. The 10-year drain rule still applies — you must empty the inherited Roth by year 10 — but there is no tax cost to leaving it untouched.

That makes the sequencing obvious: when you have both pre-tax and Roth inherited money, withdraw the pre-tax dollars first (to control bracket exposure) and let the Roth grow tax-free for the full 10 years, taking it out at the very end. Roll the Roth 401(k) to an inherited Roth IRA (not a traditional inherited IRA) to preserve its tax-free character.

Spouse vs non-spouse: completely different option sets

Everything above assumes a non-spouse beneficiary like Marcus. A surviving spouse has options no one else gets:

• Spousal rollover into your OWN IRA or 401(k). The money becomes yours outright — no 10-year drain. You take RMDs only when you reach your own RMD age (73 or 75 under SECURE 2.0 §107), and a Roth IRA you own has no lifetime RMDs at all.
• Treat it as an inherited account. Useful if you are under 59½ and might need penalty-free access — distributions from an inherited account skip the 10% penalty, while distributions from your own rolled-over IRA before 59½ would trigger it. As an eligible designated beneficiary, a spouse can stretch withdrawals over life expectancy rather than the 10-year window.

A spouse under 59½ who needs the cash often keeps it inherited first (penalty-free access), then rolls it into their own IRA after turning 59½ for the longest possible deferral. Other eligible designated beneficiaries — a minor child of the decedent, a disabled or chronically ill person, or someone less than 10 years younger than the decedent — can also stretch over life expectancy instead of the 10-year rule.

What most people miss: never take a check

The single most expensive mistake is having the 401(k) plan cut a distribution check payable to you. Two things go wrong at once.

1. Mandatory 20% withholding. Any 401(k) distribution paid to you (not transferred directly) is subject to mandatory 20% federal withholding under IRC §3405(c). On $300,000, that is $60,000 sent to the IRS before you see a dime — money you have to chase back through your tax return or replace from other funds to complete a rollover.
2. Non-spouses can’t do a 60-day rollover. A surviving spouse can redeposit the money within 60 days. A non-spouse beneficiary cannot — if a non-spouse takes a check, the distribution is permanent and fully taxable. The 10-year-smoothing strategy is gone. The only way a non-spouse preserves the inherited IRA option is a direct trustee-to-trustee transfer: the funds move from the plan straight to an inherited IRA titled correctly (e.g., “John Smith, deceased, for the benefit of Marcus Smith, beneficiary”).

Open the inherited IRA first, then instruct the 401(k) plan to send the money directly to that account. Do not let the plan mail you a check “to deposit yourself.”

The income-smoothing decision in practice

Beyond a flat 8-year split, the real optimization is to fill up your low-bracket headroom each year. Map it like this:

• Each year, estimate your other taxable income.
• Withdraw from the inherited IRA only up to the top of your current bracket (for Marcus, up to the $103,350 / 22%–24% line) so the inherited dollars never spill into 32%.
• Lean heavier in any low-income year — a sabbatical, a layoff, an early-retirement year before Social Security and RMDs — when your bracket drops and the same withdrawal costs less tax.
• Always satisfy any required year-1–9 RMD if the decedent had started RMDs, and make sure the account hits $0 by December 31 of year 10.

Key takeaways

• There is no 10% early-withdrawal penalty on an inherited 401(k) at any age (IRC §72(t)(2)(A)(ii)). The decision is bracket math, not penalties.
• A pre-tax inherited 401(k) cashed out at once is fully ordinary income — a $300K balance on a $90K salary spikes a single filer into the 35% bracket and roughly $89,000 of federal tax.
• Rolling to an inherited IRA via a trustee-to-trustee transfer lets a non-spouse spread withdrawals across the SECURE Act 10-year window, trimming the federal tax to about $67,000 and saving an estimated $22,000 on the same $300K.
• If the decedent had started RMDs, the 2024 final regs require annual RMDs in years 1–9 plus emptying by year 10; if not, you only need the account empty by year 10.
• An inherited Roth 401(k) is tax-free (5-year-held; IRC §402A) — drain it last so it compounds tax-free for the full decade.
• Never take a check. A non-spouse who does loses the rollover permanently and eats 20% mandatory withholding (IRC §3405(c)). Move money trustee-to-trustee only.
• The decision lever is which years you recognize the income — fill low brackets first, accelerate in low-income years, and keep the inherited dollars out of 32% and 35%.