Before you roll overWhat a retirement account costs, and what it forbids

Can I move money from an IRA back into a 401(k) at my new job?

By Kaz · Published 28 September 2026 · How this site checks figures

Summary

Yes for traditional IRA money, if the 401(k) is willing to take it. The IRS says you can roll an IRA into a qualified plan "assuming the retirement plan has language allowing it to accept this type of rollover," and plans aren't required to. Roth IRA money can't go into a 401(k) at all; it can only move to another Roth IRA.

The plan decides first

Everything starts with the receiving plan's document. The IRS rollovers page puts it in one line: "Your retirement plan is not required to accept rollover contributions." So the first conversation is with the new plan's administrator, who can tell you whether IRA money is accepted and which kinds.

If it is, the IRS rollover chart allows a traditional IRA to go into a pretax qualified plan, a pretax 403(b), or a governmental 457(b) with separate accounts. It does not allow a traditional IRA to go into a designated Roth account inside a workplace plan. The Roth IRA row is "No" for every workplace plan column.

Two mechanical points help. A trustee-to-trustee transfer from the IRA straight to the plan has no tax withheld, and a move from an IRA into a plan isn't counted against the once-a-year limit on IRA-to-IRA rollovers.

Only the taxable part can go

The statute caps what an IRA can send to a workplace plan. Section 408(d)(3)(A)(ii) says the amount paid into the plan "may not exceed the portion of the amount received which is includible in gross income." Your nondeductible contributions, the basis, can't make the trip.

Section 408(d)(3)(H) then overrides the usual pro-rata rule. The portion rolled to the plan is "treated as from income on the contract," up to the total income across all your IRAs. In other words, the rollover pulls out taxable dollars first and leaves the basis behind.

Take an $85,000 traditional IRA that includes $12,000 of basis from years when the contributions weren't deductible. At most $73,000 can go to the 401(k). If all $73,000 moves, the $12,000 left in the IRA is entirely basis. That is why people planning a backdoor Roth look at this move: Form 8606 figures the taxable share of a Roth conversion against the value of all traditional, SEP and SIMPLE IRAs on December 31 of the conversion year, so if no other IRA holds pre-tax money on that date, converting the $12,000 carries no pre-tax share apart from any earnings since the rollover. Form 8606 is also where that $12,000 was recorded in the first place; our piece on the backdoor Roth pro-rata rule walks through the form line by line.

Sources

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