401(k) to Roth IRA

Rolling a 401(k) to a Roth IRA is one of the most powerful retirement planning moves available to working adults—but it comes with a significant tax bill. When you roll pre-tax 401(k) money into a Roth, you owe immediate income tax on the entire converted balance. A Roth 401(k), by contrast, rolls tax-free to a Roth IRA. This guide covers the mechanics, the hidden traps (like mandatory withholding), the 5-year rule interaction, and when rolling actually makes sense despite the tax cost.

The Direct Rollover Process

A direct rollover is a trustee-to-trustee transfer from your 401(k) plan to a Roth IRA. You complete a rollover request form with your plan administrator (or online through most plans' portals), provide your new Roth IRA custodian's details, and the money transfers directly.

Typical timeline: 5-10 business days, though some custodians take up to 3 weeks depending on account type and plan complexity. Your plan administrator will send you a confirmation letter showing the transfer details. The funds land in your Roth IRA, and no 1099-R is issued (or one is issued with code "G" indicating a direct rollover).

From a tax perspective, the mechanics are clean: direct rollovers don't trigger withholding, don't have a 60-day deadline, and don't count against the one-rollover-per-year rule (that rule only applies to indirect rollovers between IRAs, not 401(k) rollovers). After the transfer settles, you report the conversion on your tax return and pay the tax due.

Pre-Tax 401(k) vs. Roth 401(k) — The Tax Difference

Pre-tax 401(k) contribution: You contributed $10,000 pre-tax. Your employer withheld taxes from your paycheck. That $10,000 was never taxed at contribution time. When you roll it to a Roth IRA, you owe income tax on the entire $10,000 as a conversion.

Roth 401(k) contribution: You contributed $10,000 post-tax. You paid federal, state, and local income tax on that $10,000 upfront. When you roll it to a Roth IRA, zero additional tax is due. The rollover is completely tax-free.

The distinction is critical. If your 401(k) contains only Roth contributions and earnings, rolling to a Roth IRA is an easy decision—no tax cost, and you gain access to better investment options and typically lower fees. (Note: Roth 401(k) lifetime RMDs were eliminated by SECURE 2.0 §325 effective 2024, so RMD avoidance is no longer a reason for the rollover.) If your 401(k) is entirely pre-tax contributions and employer match, the conversion cost is immediate and substantial.

The 20% Withholding Trap on Indirect Rollovers

If you request an indirect rollover (where the plan mails you a check), the plan is required to withhold 20% of the distribution for federal income tax. This is not optional—it's a statutory requirement for most qualified plan distributions.

Example: You have a $100,000 pre-tax 401(k) and request an indirect rollover. The plan withholds $20,000 and mails you a check for $80,000. You have 60 days to complete the rollover.

The trap: To avoid having the $20,000 withheld amount treated as a non-rollover distribution (and thus taxable), you must deposit the full $100,000 into your Roth IRA within 60 days. But you only received $80,000. You must contribute the missing $20,000 from your own pocket.

If you only deposit the $80,000, the IRS treats the $20,000 as a taxable distribution that was not rolled over. You then owe income tax on the full $100,000 (as a conversion) plus income tax again on the $20,000 (as a non-rollover distribution). It's double taxation.

Solution: Use a direct rollover instead. Direct rollovers have no withholding requirement. The full amount transfers directly, avoiding the shortfall problem entirely.

How the 5-Year Rule Interacts With 401(k) Conversions

Rolling a 401(k) to a Roth IRA triggers a conversion, which means the Roth IRA 5-year rule applies to the converted amount.

The 5-year rule: For people under 59½, converted funds (the portion that was pre-tax) are subject to a 10% early withdrawal penalty if withdrawn within 5 years of the conversion. The 5-year clock starts January 1 of the year you made the conversion and runs independently for each conversion.

Example: You convert $100,000 from a 401(k) to a Roth IRA on June 15, 2026. The 5-year clock starts January 1, 2026. If you withdraw any of the converted $100,000 before January 1, 2031, and you're under 59½, you'll owe a 10% penalty on the withdrawn amount (the tax-paid amount, not additional tax—just the penalty). However, your regular contributions and other conversions have their own separate 5-year clocks.

Practically, this matters if you're rolling over a large 401(k) balance and might need access to the money soon. A Roth IRA contribution (not a conversion) is always accessible without penalty. But converted amounts are locked for 5 years (for early withdrawal penalty purposes) if you're under 59½.

Rolling a Roth 401(k) to a Roth IRA (Tax-Free)

If your 401(k) has a Roth option, rolling the Roth portion to a Roth IRA is completely tax-free. The money was already taxed when you contributed it, so moving it between Roth accounts produces zero tax consequence.

This is often strategically valuable because Roth 401(k)s have two features that Roth IRAs don't: (1) much higher contribution limits ($24,500 in 2026 vs. $7,500 for Roth IRA), and (2) employer match (though the match goes to the pre-tax side). Rolling the Roth balance to a Roth IRA gains you access to more investment options (mutual funds, individual stocks, ETFs vs. limited 401(k) fund menus) and typically lower ongoing fees. Lifetime RMDs are no longer a factor for either account: SECURE 2.0 §325 eliminated Roth 401(k) owner RMDs effective 2024, matching the existing Roth IRA treatment.

When Rolling Your 401(k) Actually Makes Sense

Job change (separation from service): Most 401(k) plans require you to roll over or take a distribution when you leave the employer. If you have access to roll, doing so is usually wise—IRAs offer more control, lower fees, and better tax planning opportunities.

Retirement (leaving the workforce): At retirement, rolling your 401(k) to a Roth can be tax-efficient if your income is temporarily low (no other employment income). Some retirees intentionally convert large amounts in their first few years of retirement when they have no W-2 income and are below Social Security.

Better investment options: 401(k)s typically offer 10-50 mutual funds. IRAs offer access to individual stocks, ETFs, REITs, and broader investment universe. If your 401(k) fees are high or fund selection is poor, rolling to an IRA might improve your long-term returns.

Lower fees: Some 401(k) plans charge 0.5-1.5% in annual fees (advisor fees, admin fees). IRAs at major custodians typically charge 0-0.25%. Over 20-30 years, fee drag can cost hundreds of thousands. If your 401(k) is expensive, rolling to a low-cost IRA provider (Vanguard, Fidelity, Schwab) often makes economic sense.

Roth conversion opportunity: If you're in a low-tax-bracket year (early retirement, sabbatical, temporary job loss), rolling a traditional 401(k) to Roth locks in a potentially favorable conversion rate. If your income recovers, you've already paid the tax.

Partial vs. Full Rollovers

You don't have to roll the entire 401(k) balance. Most plans allow partial rollovers. You might roll $100,000 to a Roth IRA and leave $200,000 in the 401(k) with your former employer (if allowed) or with a new employer's plan.

Reasons for partial rollovers: (1) Managing conversion tax cost—rolling a large balance in one year might push you into a higher tax bracket, so you spread it over multiple years. (2) Keeping employer funds to preserve creditor protection. (3) Testing different investment strategies—rolling a portion while keeping the rest in the 401(k).

Be aware: employer match contributions (usually pre-tax) must stay in a traditional account or roll to a traditional IRA if rolling. You cannot roll employer match to a Roth IRA tax-free; it's treated as a conversion with full tax due.

In-Service Distributions and In-Service Conversions

Some 401(k) plans allow "in-service distributions" or "in-service conversions"—the ability to roll or convert funds to an IRA while you're still employed with the sponsoring company. This is less common than post-separation rollovers, but increasingly available.

An in-service conversion allows you to move traditional 401(k) funds directly to a Roth IRA (or Roth 401(k)) while still working. This is useful if you're earning high income now but expect lower income in retirement—you can start converting gradually rather than waiting for separation from service.

Check with your plan administrator whether your 401(k) allows in-service conversions. If it does, this can be a powerful tax-planning tool.