Is a 401(k) Rollover Taxable? 2026 Tax Rules Explained

The short answer: a traditional 401(k) rolled to a traditional IRA is completely tax-free. A Roth 401(k) rolled to a Roth IRA is also tax-free. Where taxes appear is when you convert a traditional 401(k) to a Roth IRA — that's an intentional taxable event, not a simple rollover. And taxes appear by accident when an indirect rollover goes wrong. This guide walks through every scenario, how it gets reported on Form 1099-R, and what state taxes apply.

Scenario 1: Traditional 401(k) → Traditional IRA — tax-free

This is the most common rollover path, and it creates zero taxable income in the year of the rollover. Under IRC § 402(c), the entire balance — your pre-tax contributions, employer match, and all investment gains — transfers to a traditional IRA without being included in your gross income for the year.¹

You will receive a Form 1099-R from your old plan administrator showing the full amount distributed. But if you executed a direct rollover — funds went directly to your IRA custodian — the form will show distribution code G and Box 2a (taxable amount) will be $0. No tax due, nothing extra to pay, nothing to add to your income.

The pre-tax money inside the IRA is still subject to income tax — but only when you actually take distributions later. Every dollar you eventually withdraw from that traditional IRA will be ordinary income in the year you take it. The rollover doesn't accelerate or avoid that tax; it defers it, exactly as the 401(k) did.

Scenario 2: Roth 401(k) → Roth IRA — also tax-free

Roth 401(k) contributions were made with after-tax dollars. Rolling them to a Roth IRA is tax-free: you've already paid tax on the contributions, and the growth transfers untouched.² Form 1099-R will show distribution code H for a direct rollover of a designated Roth account.

One timing trap to watch: the Roth IRA's five-year qualified distribution clock may be different from your Roth 401(k)'s clock. If your Roth IRA doesn't have an existing five-year clock running, the rollover starts a new one — which matters if you're under 59½ and might need the earnings. Contributions (your basis) always come out penalty-free; only earnings are affected by the five-year rule. See the full Roth 401(k) rollover guide for the details.

Scenario 3: Traditional 401(k) → Roth IRA — taxable by design

This is not a rollover in the tax-neutral sense — it's a Roth conversion. When pre-tax 401(k) money moves into a Roth IRA, every dollar is treated as ordinary income in the year of the conversion.³ Form 1099-R will show the distribution, and you'll pay federal income tax at your marginal rate on the entire converted amount.

This is not a mistake — it's a deliberate trade. You pay tax now, but those dollars and all future growth come out of the Roth IRA entirely tax-free. Whether the trade is worth it depends on your current tax rate vs. your expected rate in retirement.

2026 federal income tax brackets (taxable income after deductions)

Standard deduction (2026): $16,100 single / $32,200 married filing jointly. Source: IRS Rev. Proc. 2025-32.⁴

The converted amount stacks on top of your other income for the year. If you earn $80,000 in wages and convert $120,000, your taxable income is $200,000 — taxed at progressively higher rates as it crosses bracket thresholds. Use the Roth conversion tax calculator to estimate your exact cost.

The accidental tax event: the indirect rollover withholding trap

Even if you intended a tax-free traditional-to-traditional rollover, you can accidentally create a taxable event by using an indirect rollover instead of a direct rollover.

When you take a distribution from a 401(k) instead of initiating a plan-to-plan transfer, the plan administrator is required to withhold 20% of the distribution as a federal income tax prepayment under IRC § 3405(c).⁵ You receive only 80% of your account balance as a check.

To complete a tax-free rollover, you must deposit 100% of the original balance — including the 20% that was withheld — into an IRA within 60 days. If you can only deposit the 80% you received, the missing 20% is treated as a taxable distribution in the year it was withheld, plus a 10% early withdrawal penalty if you're under 59½.

Example: Kevin leaves his job with $200,000 in his 401(k). Instead of requesting a direct transfer, he asks the plan to "send him a check." The plan sends him $160,000 and withholds $40,000 for federal taxes. To complete a tax-free rollover, Kevin must deposit $200,000 into an IRA within 60 days — meaning he needs to find $40,000 from his savings to make up the withheld amount. If he deposits only the $160,000 he received, the $40,000 is treated as income plus potential penalty. He'll get the $40,000 back as a refund when he files his taxes, but only after he's already paid the associated tax and penalty. Total accidental tax bill on a supposedly tax-free rollover: potentially $10,000+.

See the full direct vs. indirect rollover guide to understand how to avoid this trap entirely.

When the 60-day deadline is missed

If you take a distribution and fail to deposit it into an IRA within 60 days, the entire amount becomes taxable — regardless of your original intent. The IRS provides a self-certification waiver procedure under Rev. Proc. 2016-47 for specific qualifying reasons (hospitalization, postal error, misdeposit, etc.), but ordinary forgetfulness or cash flow needs don't qualify.⁵

State income taxes on 401(k) rollovers

State income tax treatment generally tracks federal treatment for traditional-to-traditional rollovers: the rollover isn't income, so it isn't taxed. But for Roth conversions — where the federal government treats the conversion as taxable income — most states also include the conversion in your state taxable income.

A few important state-level nuances:

• No-income-tax states: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming have no state income tax — no state tax on any rollover or conversion regardless of type.
• States that exempt retirement income: Pennsylvania and Illinois exclude most retirement income from state taxation, including 401(k) distributions. A Roth conversion may be taxable federally but not at the state level in these states.
• States with partial exclusions: Many states (Georgia, South Carolina, Michigan, Mississippi, and others) allow partial exclusions for retirement income above certain ages. A Roth conversion that would fully trigger state tax at age 55 may be partially excluded at 65.
• High-tax states: California, New York, Oregon, Minnesota, and New Jersey tax Roth conversions at their full marginal state rates — which can add 6–13% on top of the federal cost.

State tax significantly affects the math on Roth conversions. A married couple in California doing a $150,000 conversion in the 22% federal bracket also pays California's 9.3%+ state rate — combined effective rate of 30%+. In Texas or Florida, they pay only the 22% federal rate. This gap often changes whether the conversion makes sense.

Form 1099-R: how rollovers get reported

Every 401(k) distribution — including rollovers — is reported on Form 1099-R by the distributing plan. The distribution code in Box 7 tells the IRS how to treat the distribution:

When you do a Roth conversion, Box 2a on your 1099-R will show the full taxable amount. That amount goes on Line 5b of Form 1040 as ordinary income. If you over-contributed or have a basis in your 401(k) (rare, but happens with after-tax contributions), you may also file Form 8606 to track the after-tax portion and avoid double taxation.

IRMAA: the Medicare surcharge cliff for large conversions

If you're on Medicare — or will be within two years — a large Roth conversion can trigger Medicare IRMAA surcharges. IRMAA is assessed based on your modified adjusted gross income (MAGI) from two years prior: your 2026 return determines your 2028 Medicare premiums.

The 2026 IRMAA first threshold is $109,000 for single filers and $218,000 for married filing jointly.⁶ Crossing this threshold by $1 triggers at least an $81.20/month surcharge per person on Medicare Part B and Part D combined — roughly $975/year per enrollee. Higher tiers add $162–$487/month per person above the first threshold.

IRMAA is a cliff, not a phase-out. A conversion that puts you $1 over the threshold costs the same surcharge as one that puts you $10,000 over. Careful bracket-filling to stay just under the threshold saves Medicare premiums for two future years.

Three scenarios: what taxes actually cost

Scenario A: Tax-free direct rollover — no cost at all

Sarah, 48, leaves her job with $420,000 in a traditional 401(k). She calls Fidelity, opens a traditional IRA, and initiates a direct transfer. Fidelity contacts the old plan administrator, receives the $420,000 directly, and deposits it as a rollover contribution.

Tax consequence: zero. No 1099-R with taxable income. No state taxes. No withholding. Sarah has $420,000 in a traditional IRA, exactly as if she'd never changed jobs — just with a wider investment menu and lower fees. She'll pay ordinary income tax when she takes distributions in retirement.

Scenario B: Roth conversion in a low-income year — deliberate and valuable

David, 55, retires early and has a gap year before he starts consulting work. His 2026 income before any conversion: $32,000. After the $16,100 standard deduction, his taxable income is $15,900 — well within the 12% bracket (which runs to $50,400 for single filers). He has $340,000 in a traditional 401(k) from his prior employer.

He converts $34,500 of the traditional 401(k) to a Roth IRA. Taxable income after conversion: $50,400 — exactly the top of the 12% bracket. Federal tax on the $34,500 conversion: approximately $4,140. Effective rate on the converted amount: 12%. He converts $34,500 per year for the next four years while income is low, moving $138,000 to Roth at 12% federal rates. No California tax — he moved to Texas before retiring. Total federal tax on all conversions: ~$16,560 to shelter $138,000 from future taxes and RMDs.

Scenario C: Large conversion hits multiple traps at once

Linda and Robert, both 64 and on Medicare, are in the 22% federal bracket. Their 2026 income before any conversion is $185,000 (pension + dividends). They want to convert $80,000 from Robert's old 401(k) before RMDs start at 75.

Total income with conversion: $265,000 — pushing them past the $211,400 top of the MFJ 22% bracket and into 24%. Federal tax on the $80,000 conversion: approximately $18,200 (partly at 22%, partly at 24%). But the bigger issue: $265,000 exceeds the $218,000 MFJ IRMAA threshold by $47,000, triggering a surcharge of at least $162/month per Medicare enrollee for two years — roughly $3,888 in extra Medicare premiums. Their $80,000 conversion effectively costs $22,088 between federal tax and IRMAA surcharges.

The better approach: convert only $33,000 — enough to reach $218,000 MAGI exactly. Tax on conversion: about $7,260. IRMAA: none. They stay under the cliff and can continue $33,000/year for the next several years before RMDs begin, building Roth balances without triggering the surcharge. This kind of precision planning is exactly what a fee-only rollover specialist does.

1. IRS Topic 413: Rollovers from Retirement Plans — traditional 401(k) direct rollover to traditional IRA excluded from gross income under IRC § 402(c); 60-day rule; one-rollover-per-year rule for IRA-to-IRA; no limit on direct plan-to-plan rollovers.
2. IRS: Rollovers of Designated Roth Account Distributions — Roth 401(k) rollover to Roth IRA tax-free; after-tax basis carries over; five-year qualified distribution clock rules after rollover.
3. IRS: Retirement Plans FAQs — Rollovers and Roth Conversions — conversion of pre-tax 401(k) to Roth IRA is taxable event; amount converted is ordinary income in year of conversion; no income limit on conversions.
4. IRS Rev. Proc. 2025-32: Tax Year 2026 Inflation Adjustments — 2026 federal income tax bracket thresholds and standard deduction ($16,100 single / $32,200 MFJ).
5. IRS Rev. Proc. 2016-47: Waivers of the 60-Day Rollover Requirement — self-certification procedure for qualifying waiver reasons; mandatory 20% withholding on 401(k) distributions under IRC § 3405(c).
6. Kiplinger: Medicare Premiums 2026 — IRMAA Brackets and Surcharges for Parts B and D — 2026 IRMAA first-tier threshold: $109,000 single / $218,000 MFJ; Part B surcharge range $81.20–$487.00/month per enrollee.

Tax bracket values verified against IRS Rev. Proc. 2025-32 as of May 2026. IRMAA thresholds from Kiplinger and CMS as of May 2026. Tax rules subject to change — consult a qualified tax advisor for your specific situation.