Yes, a 401(k) is taxed, but when you pay those taxes depends on the type of account you have. With a traditional 401(k), you skip taxes on the money going in and pay income tax on every dollar you withdraw in retirement. With a Roth 401(k), you pay taxes on your contributions upfront, then withdraw the money tax-free later. Understanding the timing makes a big difference in how much you actually keep.
How a Traditional 401(k) Is Taxed
Contributions to a traditional 401(k) are made with pre-tax dollars. That means your taxable income drops in the year you contribute, giving you an immediate tax break. If you earn $80,000 and put $10,000 into your traditional 401(k), you’re only taxed on $70,000 that year.
The trade-off comes later. When you withdraw money in retirement, the entire amount counts as ordinary income on your tax return, including both your original contributions and any investment gains that accumulated over the years. You’ll owe federal income tax at whatever bracket applies to you in retirement. If your state has an income tax, you’ll typically owe that as well. The IRS treats these withdrawals the same as a paycheck, not as capital gains, so there’s no lower tax rate for long-term growth inside the account.
How a Roth 401(k) Is Taxed
A Roth 401(k) flips the timing. Your contributions come from after-tax income, so you don’t get a tax deduction in the year you contribute. But qualified withdrawals in retirement are completely tax-free, including all the investment growth. If you contributed $200,000 over your career and it grew to $600,000, you wouldn’t owe a cent in taxes on any of it when you pull the money out.
To qualify for tax-free treatment, you generally need to be at least 59½ and have held the Roth account for at least five years. Withdrawals that don’t meet those conditions may be partially taxable.
How Employer Matches Are Taxed
If your employer matches your contributions, those matching dollars always go into the account on a pre-tax basis, even if you’re contributing to a Roth 401(k). The IRS does not tax employer contributions when they’re deposited, but you will owe ordinary income tax on those funds when you withdraw them. Investment gains on the employer match are also taxed at withdrawal. So even with a Roth 401(k), part of your eventual withdrawals will be taxable.
The 10% Penalty for Early Withdrawals
Taking money out of your 401(k) before age 59½ triggers an additional 10% early withdrawal tax on top of any regular income tax you owe. On a $20,000 early withdrawal in the 22% tax bracket, you’d owe $4,400 in income tax plus a $2,000 penalty, leaving you with $13,600.
The IRS does allow exceptions that waive the 10% penalty, though you’ll still owe income tax on traditional 401(k) distributions. Some of the most commonly used exceptions include:
- Separation from service at 55 or older: If you leave your job in or after the year you turn 55, you can withdraw from that employer’s plan penalty-free.
- Total and permanent disability
- Death of the account holder: Beneficiaries who inherit the account are not subject to the penalty.
- Substantially equal periodic payments: A series of roughly equal withdrawals taken over your life expectancy.
- Unreimbursed medical expenses exceeding 7.5% of your adjusted gross income.
- Qualified birth or adoption expenses up to $5,000 per child.
- Federally declared disaster distributions up to $22,000.
- IRS levy: Amounts seized by the IRS from your plan.
- Qualified domestic relations order: Distributions to a former spouse as part of a divorce settlement.
A few penalty exceptions that apply to IRAs do not apply to 401(k) plans. First-time homebuyer withdrawals (up to $10,000) and higher education expense withdrawals are penalty-free from an IRA but not from a 401(k). If you’re considering an early withdrawal for one of those purposes, rolling the funds into an IRA first may be worth exploring.
Required Minimum Distributions
The IRS won’t let you defer taxes on a traditional 401(k) forever. You must start taking required minimum distributions (RMDs) once you reach age 73. Each year’s RMD is calculated based on your account balance and a life expectancy factor published by the IRS, and the amount you withdraw is taxed as ordinary income.
There is one useful exception for people still working. If you’re still employed and participating in your current employer’s 401(k), you can delay RMDs from that specific plan until the year you actually retire. This doesn’t apply if you own 5% or more of the company sponsoring the plan.
Your first RMD is due by December 31 of the year you turn 73, though you can push that first one to April 1 of the following year. Delaying sounds appealing, but it means you’ll take two RMDs in the same calendar year (the delayed first one and the regular second one), which could push you into a higher tax bracket. Missing an RMD entirely is expensive: the IRS charges an excise tax of 25% on the amount you should have withdrawn. That drops to 10% if you correct the mistake within two years.
Roth 401(k) accounts were previously subject to RMDs, but starting in 2024, Roth 401(k)s are no longer required to take them. This makes the Roth 401(k) more attractive for people who want to let their money grow untouched.
How Taxes Affect Your Take-Home Amount
Your 401(k) withdrawals stack on top of any other income you have in retirement: Social Security benefits, pensions, part-time work, investment income. The combined total determines your tax bracket. Someone withdrawing $50,000 from a traditional 401(k) with $25,000 in Social Security income has $75,000 in gross income before deductions, which could land them in the 22% bracket for a portion of that money.
This is where the traditional vs. Roth decision matters most. If you expect to be in a lower tax bracket in retirement than you are now, the traditional 401(k) saves you more overall because you’re deferring taxes from a high-rate year to a low-rate year. If you expect your retirement income to be similar or higher, the Roth lets you lock in today’s rate and avoid paying more later. Many people split their contributions between both types to hedge their bets.
One detail that catches people off guard: large 401(k) withdrawals can also affect how much of your Social Security benefit is taxable, and they can increase your Medicare premiums through income-related surcharges. Planning the size and timing of your withdrawals, especially in early retirement before RMDs kick in, can meaningfully reduce your lifetime tax bill.