What to Do With an Old 401(k): Your Four Options and the Real Cost of Each

When you leave a job, you have four choices for the old 401(k): leave it where it is, roll it into your new employer's 401(k), roll it into an IRA, or cash it out. For nearly everyone, a direct rollover to an IRA or a new 401(k) is the right move, and cashing out is the costliest mistake, often losing 30-40% of the balance to taxes and penalties. The fastest way to see what your old balance could become if you keep it invested is the 401(k) calculator; this guide walks through each option, the rollover math, and the 2026 IRS limits that frame the decision.

A 401(k) does not disappear when you change jobs, but it also does not follow you automatically. The money stays parked in your former employer's plan until you decide what to do with it, and the wrong decision, especially cashing out, can permanently shrink your retirement. The good news is that the best options are simple and tax-free when done correctly. This guide compares all four paths, runs the numbers on the cash-out trap, explains the traditional-versus-Roth choice during a rollover, and states the current IRS limits so you can fit the move into a bigger plan.

Your four options at a glance

Here is the direct comparison. Three of these options keep your money growing tax-deferred; only one triggers immediate tax.

The key phrase is direct rollover, where the money moves trustee-to-trustee and never touches your bank account. A direct rollover is not taxable. An indirect rollover, where a check is mailed to you, triggers a mandatory 20% withholding and a 60-day deadline to redeposit the full amount, so it is best avoided. Whatever you choose, project the long-term result first in the 401(k) calculator.

Why cashing out is the expensive trap

Cashing out an old 401(k) before retirement age usually costs a third or more of the balance immediately, then costs far more in lost growth. If you are under age 59 and a half, a cash-out is generally taxed as ordinary income plus a 10% early-withdrawal penalty. Here is what cashing out a $25,000 balance looks like for someone in the 22% federal bracket with a 5% state tax.

That is 37% of the balance gone on the spot. The deeper cost is opportunity. Left invested at a 7% average return, that $25,000 would grow to about $135,686 over 25 years. The $15,750 you would keep after cashing out grows to only about $85,482 over the same period, a roughly $50,000 difference, and that assumes you even reinvest it. This is why a rollover almost always wins: it keeps the full balance compounding tax-deferred. To see the gap for your own number, run both the kept balance and the after-tax balance through the compound interest calculator.

Traditional or Roth: the rollover tax decision

When you roll over, you also decide whether the money lands in a traditional (pre-tax) or Roth (after-tax) account, and the choice hinges on whether your tax rate is higher now or in retirement. A traditional 401(k) rolls tax-free into a traditional IRA or new traditional 401(k); converting to Roth instead means paying income tax on the rolled amount today in exchange for tax-free withdrawals later.

The math is symmetric. Consider $10,000 a year contributed for 30 years at 7%, which grows to about $944,608 before any tax.

Roth looks better here only because this table holds the contribution fixed; a fair comparison accounts for the fact that Roth dollars are after-tax and therefore cost more out of pocket today. The honest takeaway: if your tax rate will be lower in retirement, traditional wins; if it will be higher, Roth wins; if it is the same, they tie. Many people split the difference. Note that rolling a traditional balance into a Roth is a taxable event in the year you do it, so weigh whether you can pay that tax from outside savings. Compare scenarios with the Roth IRA calculator and check your bracket-aware paycheck math in the take-home pay calculator.

The 2026 IRS limits that frame the move

A direct rollover itself is not capped, but the contribution limits matter for what you do next, and they change yearly, so confirm the current figures. For tax year 2026, the key 401(k) numbers are below.

A crucial point that trips people up: rolling over an old balance does not count against these annual contribution limits. You can roll a $25,000 old 401(k) into an IRA and still contribute the full $24,500 to your new 401(k) in the same year. Rollover money is moving existing retirement dollars, not making a new contribution. Because these figures are indexed and revised most years, treat them as 2026-only and verify the current numbers on the IRS site before planning. The official figures are published on the IRS 401(k) contribution limits page.

How to roll over an old 401(k) without a tax bill

A clean, tax-free rollover comes down to a few careful steps.

1. Pick the destination first. Decide between your new employer's 401(k) and an IRA, comparing fund choices and fees, and confirm whether you want the same tax type or a Roth conversion.
2. Open the receiving account. Set up the IRA or confirm your new 401(k) accepts rollovers, and get its exact account and routing instructions.
3. Request a direct rollover. Tell the old plan to send the money trustee-to-trustee, made payable to the receiving institution, not to you, to avoid the 20% withholding.
4. Match the tax types. Roll pre-tax money into a traditional account and Roth money into a Roth account, unless you intend a deliberate, taxable Roth conversion.
5. Confirm and reinvest. Verify the funds arrived, then make sure the money is actually invested rather than sitting in cash, so it starts compounding again.

Done this way, the entire balance keeps growing tax-deferred with no tax bill. Once the rollover is complete, fold it into your overall plan and check whether you are on track using the retirement calculator and the broader retirement calculators hub. Moving an old 401(k) correctly is one of the easiest ways to protect years of compounding you already earned.

Frequently asked questions

What should I do with my 401(k) when I leave a job?

You have four options: leave it in the old plan, roll it into your new employer's 401(k), roll it into an IRA, or cash it out. For most people, a direct rollover to an IRA or a new 401(k) is best because it keeps the money growing tax-deferred with no tax bill. Cashing out is usually the worst choice, since it triggers income tax plus a likely 10% penalty before age 59 and a half.

How much does it cost to cash out an old 401(k)?

Cashing out before age 59 and a half typically costs a third or more of the balance immediately. On a $25,000 balance for someone in the 22% federal bracket with 5% state tax, you would lose about $5,500 in federal tax, $2,500 to the 10% early-withdrawal penalty, and $1,250 in state tax, totaling $9,250, or 37% of the balance. You would keep just $15,750, and lose decades of potential compounding on top.

Is a 401(k) rollover taxable?

A direct rollover is not taxable, provided you keep the same tax type, such as traditional to traditional or Roth to Roth. The money moves trustee-to-trustee and never reaches your bank account. An indirect rollover, where a check is sent to you, triggers a mandatory 20% withholding and a 60-day deadline to redeposit the full amount. Converting traditional money to Roth during a rollover is taxable in that year.

Does a 401(k) rollover count toward my contribution limit?

No. Rolling over an old 401(k) does not count against your annual contribution limit, because it moves existing retirement dollars rather than making a new contribution. For 2026 you can roll over any amount and still contribute the full $24,500 employee limit to your new 401(k) in the same year, plus catch-up contributions if you are 50 or older. Always verify the current-year limits, since they change.

Should I roll my old 401(k) into an IRA or my new 401(k)?

Both keep your money tax-deferred, so it depends on fees and features. An IRA usually offers the widest choice of low-cost funds and full control, which suits many savers. Rolling into your new 401(k) keeps everything in one account, may allow loans, and can offer stronger creditor protection in some states. Compare the fund menus and expense ratios of both, then choose the one with lower costs and the features you value.

Should a 401(k) rollover be traditional or Roth?

Match it to whether your tax rate will be higher now or in retirement. Rolling traditional to traditional stays tax-free now and is taxed on withdrawal, which wins if your retirement rate is lower. Converting to Roth means paying income tax today for tax-free withdrawals later, which wins if your future rate is higher. If the rates are equal, the two are mathematically identical, so many people split between both.

Can I leave my 401(k) with my old employer?

Yes, in most cases you can leave the balance in the former employer's plan if it is above the plan's minimum, often around $7,000. This makes sense when the old plan has excellent low-cost funds you cannot easily replicate elsewhere. The downsides are that you can no longer contribute, the plan may charge fees, and tracking multiple old accounts gets harder over time. Compare its funds and fees against an IRA before deciding.

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