Convert IRA or 401k First? A Sequencing Guide

If you hold both a traditional IRA and a 401(k) and want to know whether to convert IRA or 401k first, the source account rarely changes your tax rate. What changes the order are three mechanical levers: the pro-rata (backdoor Roth) rule, the net unrealized appreciation (NUA) election on employer stock, and where you get better creditor, RMD, and access treatment.

This is a sequencing question, not a “what is a Roth conversion” question. You already understand that a conversion is taxable ordinary income in the year you do it and that it is irreversible. The open item is order and path. Because Q3 Advisors approaches Roth conversion planning as a multi-year, bracket-filling exercise, the account you draw from in any single year matters far less than the total you convert across your gap years. For the size of those annual slices, our overview of how much to convert to Roth covers the annual sizing.

IRA or 401(k) first? The 60-second decision tree

Most savers can settle the order with three questions. Each one flags a special rule that overrides the default. When none applies, the account of origin is close to tax-neutral, and the decision collapses to a simple question of bracket-fill room in the current year. Working the branches in order matters, because the first two can quietly poison a strategy the third assumes is available.

• Are you doing or planning a backdoor Roth? If yes, converting the traditional IRA first is generally avoided. One approach many households use is to move (reverse-roll) the pre-tax IRA balance into the 401(k) so the IRA is empty of pre-tax dollars, then convert 401(k)-origin money separately.
• Does the 401(k) hold appreciated employer stock? If yes, the NUA question is typically resolved before any rollover, because rolling that stock into an IRA can forfeit the NUA tax treatment permanently.
• Neither applies? The account with the most room to fill a target bracket this year is often the one converted. The account of origin is nearly tax-neutral.

Why the source account barely changes the tax bill

Pre-tax dollars are taxed as ordinary income when converted, whether they sit in the IRA or the 401(k). The rate is driven by your taxable income, not by the account label. The real differences between the two accounts are mechanical: the pro-rata aggregation rule, the NUA election, creditor protection, and RMD timing. Those levers, not the tax rate, decide the order.

Should you roll the 401(k) into an IRA before converting?

The intermediate step of rolling a 401(k) to a traditional IRA before converting is no longer required. Since the pension rules were modernized, a direct 401(k) to Roth IRA conversion is allowed. Rolling to a traditional IRA first is still useful when you want granular control: converting slices across multiple tax years, accessing a wider investment menu, or doing partial conversions your plan may not permit.

Many plans process a Roth conversion only as an all-or-nothing lump sum, which can push a single year deep into the 32% or 35% bracket. Routing through a traditional IRA restores the ability to convert in measured annual amounts, which is central to a Roth conversion ladder and to bracket management generally.

When staying in the 401(k) wins

Leaving money in the plan has three educational advantages worth weighing. First, ERISA creditor protection: qualified plan assets carry broad federal protection, while rolled-over IRA protection varies by state. Second, the Rule of 55 allows penalty-free 401(k) withdrawals if you separate from service at 55 or later, versus 59 1/2 for an IRA. Third, keeping pre-tax dollars in the plan preserves a clean backdoor Roth.

Converting the 401(k) directly to Roth, or routing through a traditional IRA?

Both paths produce an identical tax result: pre-tax dollars and their earnings are taxed as ordinary income, and any after-tax (nondeductible) 401(k) contributions ride into the Roth tax-free. The difference is control. A direct conversion is one step but may be forced as a lump sum. Routing through a traditional IRA is two steps but lets you size each slice and spread it across years.

In-plan Roth conversion: the third path

Some plans let you convert inside the 401(k) itself. The dollars stay under ERISA, keeping their federal creditor protection, and there is no new 5-year clock if you are already 59 1/2. This path also keeps the balance out of the pro-rata IRA pool. As a further benefit, a Roth 401(k) is no longer subject to lifetime required minimum distributions, a change effective in 2024 under SECURE 2.0.

The pro-rata trap that dictates the order

This is the rule that most often decides whether to convert the IRA or the 401(k) first. The IRS aggregates all of your traditional, SEP, and SIMPLE IRAs into a single pool and measures the balance on December 31 of the conversion year. Any after-tax basis is spread pro-rata across every dollar you convert. Rolling a pre-tax 401(k) into an IRA inflates that pool and dilutes a backdoor Roth.

An illustrative example: suppose you make a $7,000 nondeductible IRA contribution and, in the same year, roll $100,000 of pre-tax 401(k) money into a traditional IRA. Your year-end IRA pool is $107,000, of which only $7,000 is after-tax basis. That basis is about 6.5% of the pool, so a $7,000 conversion is only about 6.5% tax-free and roughly 93.5% taxable. The clean backdoor Roth you intended is largely undone.

A common fix: reverse-rolling pre-tax IRA money into the 401(k)

Most 401(k) plans accept incoming rollovers of pre-tax IRA dollars. Moving your deductible IRA balance into the plan empties the pro-rata pool of pre-tax money. You can then make the nondeductible contribution and convert it cleanly, while converting 401(k)-origin dollars separately (in-plan or after a later rollover). Sequencing here is not optional: the pool is measured on December 31, so the reverse-roll must land before year-end.

Special case: employer stock and the NUA election

If your 401(k) holds appreciated company stock, the order of operations is a hard gate. Rolling the entire account into an IRA (traditional or Roth) can forfeit net unrealized appreciation treatment permanently. NUA lets you distribute the stock in-kind to a taxable account, pay ordinary income tax only on the cost basis, and treat the appreciation as long-term capital gain when you sell.

The distinction matters because ordinary income rates run up to 37%, while long-term capital gains fall in the 0% to 20% range. Converting the appreciation away from ordinary rates is the entire point of NUA. A split is allowed: distribute the employer stock under NUA to a taxable account, then roll or convert the remaining plan assets. This is generally resolved before any rollover, not after.

Timing rules that change the sequence

Two clocks reshape the order. In any year you owe a required minimum distribution, that RMD must come out first and can never be converted to Roth. Separately, each conversion starts its own 5-year clock governing penalty-free access to the converted principal before age 59 1/2. These rules push most conversion activity into the gap years after work income stops and before RMDs begin.

• RMD-first ordering. RMDs begin at age 73 in 2026. In an RMD year, you must satisfy the year’s distribution before rolling over or converting anything, and RMD dollars are never convertible. Details on divisors and timing are in our required minimum distributions 2026 guide.
• The per-conversion 5-year clock. Each conversion carries a separate 5-year clock for penalty-free access to that converted principal. The clock is not relevant once you are past 59 1/2.
• Gap years are a common conversion window. The post-retirement, pre-RMD years often carry unusually low taxable income. Filling to the top of a target bracket in those years is a common approach, and our Roth conversion break-even discussion covers when that math tends to favor acting sooner.

Putting it in order: three worked scenarios

These illustrative scenarios show how the levers resolve into a sequence. They are educational examples, not recommendations or promised outcomes. Each assumes the saver holds both a traditional IRA and a 401(k), and each ties the account order back to the same goal: converting the right total across multiple years while managing the bracket you land in.

Scenario A: high earner still using the backdoor Roth

A worker earning $400,000 wants to keep contributing to a Roth via the backdoor. Converting the traditional IRA first would leave a pre-tax balance in the pool and taint the conversion. One approach: reverse-roll the pre-tax IRA into the 401(k), convert nothing from the IRA, and handle any 401(k) conversion in-plan. The IRA stays empty of pre-tax dollars, so each year’s backdoor step converts cleanly.

Scenario B: retiree, no company stock, low-income gap years

A retiree with modest income before age 73 has room inside the 22% and 24% brackets. One approach: roll the 401(k) into a traditional IRA for control, then convert in annual slices sized to the top of the target bracket. With a 2026 24% bracket reaching $201,775 (single) or $403,550 (married filing jointly), the gap years offer meaningful bracket-fill room.

Scenario C: retiree with concentrated employer stock

A retiree holds appreciated company stock inside the 401(k). Rolling the whole plan to an IRA would forfeit NUA. One approach: distribute the employer stock in-kind under NUA to a taxable account first, then roll or convert the remaining plan assets in bracket-filling slices. The order protects the capital-gains treatment on the appreciation while still building the Roth over time.

A short checklist

• Confirming whether a backdoor Roth is in play is typically the first step; if so, keeping the pre-tax IRA empty preserves it.
• Checking the 401(k) for appreciated employer stock, and pricing out NUA before rolling, is a common next step.
• In an RMD year, the year’s distribution generally comes out first.
• One decision is between a direct conversion, a rollover-then-convert, or an in-plan conversion, based on the control needed.
• Sizing the year’s slice to a target bracket, then confirming the mechanics with a CPA or advisor, is where many plans land.

Frequently asked questions

What percentage of a backdoor Roth becomes taxable if I roll a pre-tax 401(k) into an IRA the same year?

In the illustrative case of a $7,000 nondeductible contribution plus a $100,000 pre-tax 401(k) rollover, the year-end IRA pool is $107,000 with $7,000 of after-tax basis. That basis is about 6.5% of the pool, so a $7,000 conversion is roughly 6.5% tax-free and about 93.5% taxable under the pro-rata rule.

On what date does the IRS measure my IRA balance for the pro-rata calculation?

The IRS aggregates all traditional, SEP, and SIMPLE IRAs and measures the combined balance on December 31 of the conversion year, reported on Form 8606. Because the snapshot is a year-end figure, a reverse-roll of pre-tax dollars into a 401(k) has to be completed before December 31 to keep those dollars out of the pro-rata pool.

Does rolling employer stock into a Roth IRA preserve or forfeit NUA?

Rolling appreciated employer stock into an IRA (traditional or Roth) generally forfeits net unrealized appreciation treatment. NUA moves the appreciation from ordinary income rates (up to 37%) to long-term capital gains (0% to 20%). You may split the account: distribute the stock in-kind under NUA to a taxable account, then roll or convert the remaining assets.

What is the Rule of 55, and how does it differ from IRA access?

The Rule of 55 lets you take penalty-free withdrawals from your current employer’s 401(k) if you separate from service in or after the year you turn 55. Once money is rolled into an IRA, that exception no longer applies, and the standard penalty-free age of 59 1/2 governs. This is one reason some savers leave funds in the plan.

At what age do RMDs begin in 2026, and can the RMD be converted?

Required minimum distributions begin at age 73 in 2026. In any RMD year you must take the year’s distribution before rolling over or converting, and RMD dollars can never be converted to Roth. A conversion done in an RMD year reduces future RMDs only for the amounts converted after the current year’s distribution is satisfied.

Is a Roth 401(k) subject to required minimum distributions?

No. Starting in 2024, under SECURE 2.0, designated Roth accounts inside a 401(k) are no longer subject to lifetime required minimum distributions for the original owner. That change removed a long-standing reason to roll a Roth 401(k) into a Roth IRA solely to escape RMDs, though other factors may still favor a rollover.

How long is the 5-year clock on each conversion?

Each Roth conversion starts its own separate 5-year clock governing penalty-free access to that converted principal before age 59 1/2. The clocks do not merge, so conversions in different years mature on different dates. Once you are past 59 1/2, the conversion 5-year rule for the 10% penalty no longer applies to accessing converted principal.

How are after-tax 401(k) contributions treated when I convert?

After-tax (nondeductible) 401(k) contributions convert to Roth tax-free, because you already paid tax on those dollars. Only the pre-tax contributions and all earnings are taxed as ordinary income at conversion. This holds whether you convert directly, route through a traditional IRA, or use an in-plan conversion, so the basis is not taxed twice.

Does the source account change my Roth conversion tax rate?

No. Pre-tax dollars are taxed as ordinary income at conversion regardless of whether they originate in the IRA or the 401(k). The differences between the accounts are mechanical: pro-rata aggregation, NUA, creditor protection, and RMD timing. Your rate is set by your taxable income for the year, which is why bracket management, not account choice, drives most conversion plans.