What to do with an old 401(k)
A 401(k) you left behind at an old job isn’t lost — but ignored, it can drift into high fees, forgotten investments, or, worst of all, a tempting cash-out that hands a third of it to the IRS. You have exactly four choices, and the gap between the best and the worst is enormous. Here’s how each option works, the rollover rules that protect your money, the federal angle most articles miss, and a calculator that shows the true price of cashing out.
1. Don’t just leave it drifting
The average worker changes jobs many times over a career, and each old 401(k) left behind is one more account quietly doing its own thing — sometimes in a stale target-date fund, sometimes bleeding fees, often simply forgotten. None of that is catastrophic, but inattention has a cost, and the moment you change jobs is the moment to make a deliberate decision rather than a default one.
The encouraging news is that the menu is short. There are only four things you can do with an old 401(k), and three of them keep your money working tax-deferred. The fourth — cashing out — is the one to understand precisely, because it’s by far the most expensive, and it’s the one people reach for in a pinch without doing the math.
2. Your four options at a glance
| Option | Best when… | Watch out for |
|---|---|---|
| Leave it in the old plan | The plan is excellent and low-cost, or you want Rule-of-55 access | Can’t add money; small balances may be forced out |
| Roll to your new 401(k) | Your new plan is solid and you value one login and RMD simplicity | Investment menu limited to that plan’s lineup |
| Roll to an IRA | You want the widest investment choice and full control | Loses Rule of 55; can complicate a backdoor Roth |
| Cash out | A true emergency with no other option | Income tax plus a 10% penalty under 59½ |
A crucial point that calms a lot of anxiety: rolling over does not count against your annual contribution limit. Moving a $200,000 balance into an IRA doesn’t touch your ability to contribute that year — a rollover is a transfer, not a contribution. And match the tax type: a traditional (pre-tax) 401(k) rolls into a traditional IRA, while a Roth 401(k) rolls into a Roth IRA, all tax-free if done correctly.
3. Direct vs. indirect rollovers
If you decide to roll over — the right call for most people — how you do it matters enormously. There are two methods, and one is far safer.
A direct rollover moves the money custodian-to-custodian. The check is made payable to the new account (not to you), so the money never passes through your hands. There’s no withholding, no 60-day clock, and no risk — the funds stay tax-deferred the entire time. This is the method to use, full stop.
An indirect rollover is the trap. The plan sends the money to you, and you have 60 days to deposit the full amount into a new retirement account. Two things bite here. First, employer plans must withhold 20% for taxes — so on a $100,000 balance you receive only $80,000. Second, to complete a full rollover you have to replace that missing $20,000 from your own pocket; whatever you don’t redeposit within 60 days becomes a taxable distribution, plus a 10% penalty if you’re under 59½. You can also only do one indirect IRA rollover per 12-month period. The fix is simple: ask for a direct rollover every time.
When you call the old plan, say: “I want a direct rollover, with the check made payable to my new custodian for benefit of my account.” That one sentence sidesteps the 20% withholding and the 60-day deadline entirely.
4. The true cost of cashing out
Cashing out feels like getting your money. It isn’t — it’s getting a fraction of your money and torching the rest. A traditional 401(k) cash-out is hit twice: the entire amount is taxed as ordinary income, and if you’re under 59½ there’s an additional 10% penalty. Between federal income tax, the penalty, and often state tax, a third to nearly half of the balance can evaporate immediately.
But the immediate tax hit is the smaller loss. The bigger one is everything that money would have become. A balance left invested compounds for decades; cashed out, it compounds for no one. The calculator below makes both losses concrete — the tax you’d pay today, and the far larger sum you’d forfeit by retirement.
5. Run your own numbers
Enter an old-401(k) balance, your age, and your tax bracket. The calculator shows what you’d actually pocket after cashing out — and what that same balance could grow to by age 65 if you rolled it over instead.
Your numbers
Assumes a traditional (pre-tax) 401(k), 7% average annual growth to age 65, and your single marginal rate applied to the whole balance. Ignores state tax and bracket effects. Educational only, not tax advice.
6. The Rule of 55 (don’t roll too soon)
Here’s the exception that should make you pause before rolling everything into an IRA. The Rule of 55 lets you take penalty-free withdrawals from your employer’s 401(k) if you leave that job in or after the calendar year you turn 55 (age 50 for many public-safety workers). It’s a powerful bridge for anyone retiring or changing careers in their late 50s who might need the money before 59½.
The catch: it applies only to the plan at the employer you separated from, and only while the money stays in that 401(k). Roll it into an IRA and the Rule of 55 vanishes — you’re back to waiting until 59½ to avoid the penalty. So if there’s any chance you’ll need that balance between 55 and 59½, leaving it in the 401(k) can be the smartest move, even if an IRA would otherwise offer better funds.
If you’re separating in your mid-50s, decide on Rule-of-55 access before you roll anything over. A rollover is easy to do and impossible to undo for this purpose — once the money’s in an IRA, the 55 door is closed.
7. The federal angle: rolling into the TSP
Most “old 401(k)” guides never mention the option that’s often best for federal employees: roll the old balance into the Thrift Savings Plan. The TSP accepts rollovers of eligible pre-tax balances from a former employer’s 401(k), 403(b), or traditional IRA, and Roth 401(k) money can roll into the Roth TSP.
Why bother? Fees. The TSP’s expense ratios are among the lowest of any retirement vehicle anywhere — a fraction of what many private-sector 401(k)s and retail funds charge. Consolidating a scattered old 401(k) into the TSP can quietly cut your investment costs while collapsing several logins into one. The trade-off is choice: the TSP offers a short menu of index funds and lifecycle funds rather than an IRA’s vast universe. But if your goal is simple, rock-bottom-cost index investing — which is the right goal for most people — the TSP is exceptionally hard to beat. Compare the approaches in our dispatch on the TSP vs. Fidelity and Vanguard.
8. IRA vs. new 401(k): how to choose
For most people who decide to consolidate, the real choice is between rolling into an IRA and rolling into the new employer’s plan (or the TSP). Each has a genuine edge:
| Roll into an IRA when… | Roll into a 401(k)/TSP when… |
|---|---|
| You want the widest possible fund selection | The plan’s funds are excellent and ultra-low-cost (e.g. the TSP) |
| You want one consolidated account you control | You value strong ERISA creditor protection |
| You don’t plan a backdoor Roth strategy | You do use a backdoor Roth (pre-tax IRA money triggers the pro-rata trap) |
| You’re comfortable past 59½ for access | You may want Rule-of-55 access before 59½ |
There’s no universal winner — the right answer turns on fees, the funds available, your age, and your tax strategy. What’s nearly universal is the method: whichever destination you choose, move the money by direct rollover, and keep traditional with traditional, Roth with Roth. Then fold the result into your broader plan, including a sensible withdrawal order once you reach retirement.
9. Frequently asked questions
What are my options for an old 401(k)?
You have four. You can leave it in your former employer’s plan (if the balance is above the plan’s minimum, often $5,000). You can roll it into your new employer’s 401(k) if they accept rollovers. You can roll it into an IRA, which usually offers the most investment choices and consolidation. Or you can cash it out, which is almost always the worst choice because you’ll owe ordinary income tax plus a 10% early-withdrawal penalty if you’re under 59½. For most people the decision comes down to a direct rollover into an IRA or into the new plan; cashing out should be a genuine last resort.
What is the difference between a direct and indirect rollover?
In a direct rollover, the money moves custodian-to-custodian — the check is made out to the new account, never to you. There’s no withholding, no 60-day deadline, and the funds stay tax-deferred the whole time. In an indirect rollover, the plan sends the money to you, and you have 60 days to deposit the full amount into a new retirement account. Employer plans must withhold 20% for taxes on an indirect rollover, and you have to make up that withheld 20% from other funds to roll over the full balance — or the shortfall is treated as a taxable distribution, with a 10% penalty if you’re under 59½. Always choose a direct rollover when you can.
How much does cashing out a 401(k) cost?
A lot. Cashing out a traditional 401(k) before age 59½ means the full amount is taxed as ordinary income, plus a 10% early-withdrawal penalty. Someone in the 22% bracket cashing out $50,000 under 59½ loses about $11,000 to income tax and $5,000 to the penalty, netting roughly $34,000. Worse is the opportunity cost: that same $50,000 left invested and growing at 7% could be worth several times the cash-out amount by retirement. The calculator on this page shows both the immediate tax hit and the long-term growth you’d give up.
What is the Rule of 55?
The Rule of 55 lets you take penalty-free withdrawals from your employer’s 401(k) if you leave that job in or after the calendar year you turn 55 (50 for certain public-safety workers). It applies only to the plan at the employer you separated from, and only while the money stays in that 401(k). If you roll the balance into an IRA, you lose Rule-of-55 access and generally can’t take penalty-free withdrawals until 59½. So if you’re retiring or leaving a job in your mid-to-late 50s and may need that money before 59½, leaving it in the 401(k) can be the smarter move.
Can a federal employee roll an old 401(k) into the TSP?
Yes. The Thrift Savings Plan accepts rollovers of eligible pre-tax balances from a former employer’s 401(k), 403(b), or traditional IRA, and Roth 401(k) balances can roll into the Roth TSP. For many federal employees this is attractive because the TSP’s expense ratios are among the lowest available anywhere, so consolidating an old private-sector 401(k) into the TSP can cut fees while simplifying your accounts. The trade-off is the TSP’s limited menu of funds compared with an IRA’s wide universe — but for low-cost, simple index investing, the TSP is hard to beat.
- IRS, “Rollovers of Retirement Plan and IRA Distributions”
- Fidelity, “What Is the 60-Day Rollover Rule?”
- IRS, “Topic 558: Additional Tax on Early Distributions” (Rule of 55)
- TSP.gov, “Move Money Into the TSP”
- IRS, “Rollover Chart” (which accounts roll where)
- Empower, “Rollover IRA Taxes and the 60-Day Rule”