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 appreciated employer stock, and where you get better creditor, access, and RMD treatment.
To convert IRA or 401k first, let the mechanics decide, not the tax rate. Convert the account with the most room to fill your target bracket this year, unless a special rule intervenes: if you plan a backdoor Roth, keep pre-tax dollars inside the 401(k) and convert it; if the 401(k) holds appreciated employer stock, settle NUA before any rollover. Pre-tax dollars are taxed the same either way.
This is a sequencing question, not a “what is a Roth conversion” question. Because Q3 Advisors treats 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, which our overview of how much to convert to Roth helps you size.
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IRA or 401(k) first? The 60-second decision tree
Most savers can settle whether to convert the IRA or the 401(k) first with three questions. Each flags a special rule that overrides the default. When none applies, the account of origin is close to tax-neutral, and the choice collapses to bracket-fill room in the current year. Work the branches in order, 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. Many households 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, because 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 for the year, not the account label. The real differences between the two accounts are mechanical: pro-rata aggregation, 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?
You do not have to roll a 401(k) into a traditional IRA before converting to Roth; 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 making 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 measured annual conversions, spreading the tax across several years instead of paying it all at once.
When staying in the 401(k) wins
Leaving money in the plan has three educational advantages. 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 age 55 or later, versus age 59 1/2 for an IRA. Third, keeping pre-tax dollars in the plan preserves a clean backdoor Roth.
Three paths to convert a 401(k): direct, rollover-then-convert, in-plan
All three paths produce the same 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; a rollover-then-convert is two steps but lets you size each slice; an in-plan conversion keeps dollars under ERISA and out of the pro-rata pool.
| Feature | Direct 401(k) to Roth IRA | 401(k) to traditional IRA, then convert | In-plan Roth conversion |
|---|---|---|---|
| Steps | One | Two | One (stays in plan) |
| Partial-amount control | Plan may force lump sum | Full control, any slice | Depends on plan rules |
| Multi-year spreading | Limited by plan | Yes, convert annually | Depends on plan rules |
| Creditor protection | Moves to IRA (state law) | Moves to IRA (state law) | Stays under ERISA |
| After-tax basis | Converts tax-free | Converts tax-free | Converts tax-free |
| Effect on pro-rata pool | No new pre-tax IRA balance | Inflates pre-tax IRA pool | Keeps balance out of pool |
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 age 59 1/2. This path also keeps the balance out of the pro-rata IRA pool. 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 rule that dictates the order
The pro-rata rule 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, so 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, 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, converting 401(k)-origin dollars separately. 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. A split is allowed: distribute the employer stock under NUA to a taxable account, then roll or convert the remaining plan assets. Resolve this before any rollover, not after.
2026 contribution limits and the match-first rule
Contribution room feeds the conversion decision, because a backdoor Roth starts with a fresh nondeductible IRA contribution and match dollars usually come first. For 2026, the IRA limit is $7,500 ($8,600 if age 50 or older) and the 401(k) employee deferral limit is $24,500. Many savers capture the full employer match before directing dollars to conversions, since the match is an immediate return the conversion order does not replace.
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 for 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, and RMD dollars are never convertible. See 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, which stops mattering once you are past age 59 1/2.
- MAGI side effects. A conversion is not itself net investment income, but it raises modified adjusted gross income, which can trigger the 3.8% net investment income tax on other income and lift Medicare IRMAA tiers two years later.
- The December 31 deadline. A conversion counts in the year the funds leave the account, with no grace period into April. Our Roth conversion deadline and break-even guides cover when acting sooner tends to pay off.
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 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 through 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, 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. The 2026 24% bracket reaches $201,775 (single) or $403,550 (married filing jointly), so 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), and 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, protecting the capital-gains treatment while still building the Roth.
Work with Q3 Advisors
Q3 Advisors is a registered investment adviser focused on retirement tax planning. This page is educational and is not advice; consult a qualified professional.
Frequently asked questions
Should I convert my 401(k) or IRA to Roth first?
Convert the account with the most room to fill your target bracket this year, unless a special rule applies. If you plan a backdoor Roth, keep pre-tax dollars inside the 401(k) and avoid converting the traditional IRA first. If the 401(k) holds appreciated employer stock, settle NUA before any rollover. Otherwise the source account is nearly tax-neutral.
Do I have to roll my 401(k) into an IRA before converting to a Roth?
No. A direct 401(k) to Roth IRA conversion is allowed, so the intermediate traditional IRA step is not required. Many savers still route through a traditional IRA to gain control: converting in annual slices, using a wider investment menu, or making partial conversions the plan may not permit. Both paths tax pre-tax dollars as ordinary income identically.
How do I avoid the pro-rata rule on a backdoor Roth?
Empty the pro-rata pool of pre-tax dollars before December 31 of the conversion year. Most 401(k) plans accept incoming rollovers, so reverse-rolling your deductible traditional, SEP, and SIMPLE IRA balances into the 401(k) leaves only after-tax basis in the IRA. The nondeductible contribution then converts cleanly, because the IRS measures the aggregate IRA balance on December 31.
Can I convert my 401(k) to a Roth IRA while still employed?
Sometimes. It depends on whether your plan permits in-service distributions or rollovers, which many plans allow after age 59 1/2 and some allow earlier for specific money types. If in-service moves are not available, an in-plan Roth conversion may be, keeping the dollars under ERISA. Check your summary plan description or ask the plan administrator for the specific rules.
Is it better to convert a 401(k) to a Roth 401(k) or a Roth IRA?
Both remove future taxation on qualified withdrawals, and neither is subject to lifetime RMDs for the owner as of 2024 under SECURE 2.0. A Roth 401(k) keeps ERISA creditor protection and stays out of the pro-rata IRA pool. A Roth IRA offers a wider investment menu and easier partial conversions. The right choice depends on control, access, and creditor priorities.
What is the 5-year rule for Roth conversions?
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 age 59 1/2, this conversion 5-year rule for the 10% penalty no longer applies to accessing converted principal.
Does converting a 401(k) to a Roth IRA count as income?
Yes. The pre-tax amount converted is taxable ordinary income in the year of the conversion, reported on Form 1099-R. Any after-tax (nondeductible) basis converts tax-free. A conversion is not itself net investment income, but it raises modified adjusted gross income, which can affect the 3.8% NIIT on other income and Medicare IRMAA tiers.
