What to Do With an Old 401(k) When You Change Jobs

Every time you leave a job, you leave behind a decision: what happens to the 401(k) you were contributing to. Most people don't make that decision. They just leave the account where it is and move on. That's not automatically wrong, but it's often not a choice — it's a default.

Here's what's actually at stake, what your options are, and the specific mistakes that turn a simple rollover into a tax headache.

This is a bigger problem than it sounds

Old 401(k)s don't stay small. According to an analysis by Capitalize in partnership with the Center for Retirement Research, the number of forgotten or left-behind 401(k) accounts in the U.S. has almost doubled in the last decade to an estimated 31.9 million accounts as of July 2025, containing $2.13 trillion in assets. The average forgotten account isn't pocket change either — the average account balance of a forgotten 401(k) has increased to $66,691, and assets left behind by job changers represent almost 25% of total 401(k) savings. The same analysis estimated that a forgotten account could cost an individual over $500,000 in foregone retirement savings over 30 years in a worst-case scenario, largely from higher fees and misallocated investments that no one is monitoring.

None of this means you have to move your money the moment you leave a job. It means you should make an actual decision instead of letting inertia make it for you.

Your four options

When you leave an employer, you generally have four choices for the 401(k) balance you built up there.

1. Leave it where it is

Most plans let you keep your money in a former employer's 401(k) if your balance is above a certain threshold — often $7,000, since a recent law, Secure 2.0, raised that threshold to $7,000 from $5,000 in 2024 . If your balance is below whatever cutoff your old plan sets, the plan may force the money out automatically, either as a check to you (if under $1,000) or as an automatic rollover into a default IRA.

Leaving it in place can make sense if the old plan has strong, low-cost investment options. The tradeoffs: once you leave, you can no longer contribute or receive any employer match, and 401(k) plans may have higher fees, limited investment options, and stricter withdrawal rules than other options .

2. Roll it into your new employer's 401(k)

If your new job offers a plan that accepts rollovers, you can consolidate your old balance into it. This keeps everything in one place and under one login, which makes it far easier to actually manage your allocation instead of forgetting the account exists.

3. Roll it into an IRA

This is the most common recommendation, and for good reason. IRAs generally have more investment options, no or low administration fees, and greater withdrawal flexibility compared to an employer plan. You're not limited to whatever fund lineup your old employer negotiated — you can choose almost any stock, bond, ETF, or fund available on the open market.

4. Cash it out

Technically an option. Almost never a good one. If you're under 59½, you'll face a 10% penalty unless an exception applies, and the money becomes taxable income, which could push you into a higher tax bracket . Cashing out a $50,000 balance in your 30s doesn't just cost you the taxes and penalty today — it erases decades of compounding you can't get back.

Direct rollover vs. indirect rollover: the mistake that costs people money

This is the part people get wrong, and it's expensive when they do.

A direct rollover means your old plan sends the money straight to your new IRA or 401(k) provider — you never touch it. A direct rollover does not create a taxable event, and because the individual never receives the funds, the 60-day rule and the mandatory 20% withholding do not apply. This is the option you want almost every time.

An indirect rollover means the check gets made out to you first. If you go this route, workplace plans, like traditional 401(k)s, are required to withhold 20% for taxes automatically — even if you fully intend to roll the entire amount over. So on a $40,000 balance, you'd receive a check for $32,000.

Here's the trap: to complete the rollover tax-free, you have to reinvest the full amount of your original balance — not just the 80% you received — within 60 days . That means coming up with the missing 20% out of pocket to deposit the full amount, or the withheld portion gets treated as a taxable distribution (plus a possible 10% penalty if you're under 59½). You do eventually get the withheld 20% back, but only when you file your federal income taxes — months later.

The fix is simple: always request a direct, trustee-to-trustee transfer. Never let the check get cut to you personally unless you have a specific reason to need the cash briefly.

A few exceptions worth knowing

Before you roll everything into an IRA on autopilot, know these two situations where staying in a 401(k) actually has an advantage.

• The Rule of 55: The rule of 55 is an IRS provision that allows you to withdraw money from your 401(k) or other qualified retirement plan without the 10% early withdrawal penalty if you leave your job in or after the year you turn 55. But this only applies to the plan of the employer you just left — if you roll your workplace plan into an IRA after leaving your job, the Rule of 55 no longer applies, since IRAs follow the standard 59½ rule . If you're close to that age and might need the money before 59½, think twice before rolling it over.
• Creditor protection: Under federal law, assets in a 401(k) are typically protected from claims by creditors , while IRA protection varies more by state.

How to actually do it

Whichever option you choose, the process is straightforward:

• Call the new provider (new employer's 401(k) administrator or the IRA custodian) and ask them to initiate the rollover — most will handle the paperwork for you.
• Confirm with your old plan that the transfer will be processed as a direct, institution-to-institution rollover.
• Check that your money actually lands in an investment, not just cash. Rollover IRAs sometimes default to a money market fund until you pick your own investments.
• Set a calendar reminder to check the account was funded correctly within a few weeks.

If you're not sure whether your retirement accounts, savings, and debt are actually pointed in the right direction, running your numbers through a tool like Grade My Finance's financial health check can show you where an old, forgotten account (or a fee-heavy one) is quietly dragging down your overall picture.

The bottom line

An old 401(k) isn't a problem you have to solve today, but it is a decision you should actually make rather than avoid. Leaving it behind by default risks higher fees, outdated investment choices, and — over enough years — real money. Pick a direct rollover, confirm it landed correctly, and move on knowing the account is actually working for you.