You pay taxes on 401(k) money, but when and how much depends on the type of account and when you withdraw

A traditional 401(k) lets you contribute money before taxes are taken out of your paycheck, which lowers your taxable income that year. When you withdraw that money later, you pay income tax on the full amount at your ordinary tax rate. A Roth 401(k) works the opposite way: you contribute after-tax dollars now, and withdrawals in retirement are tax-free if you meet the rules. Either way, the money does get taxed — the difference is whether you pay now or later.

The tax bill also depends on your age when you withdraw, how long the money has been in the account, and whether you take money out early. If you withdraw before age 59½ from a traditional 401(k), you typically owe income tax plus a 10 percent early withdrawal penalty on top. Roth accounts have different early withdrawal rules that can let you access contributions without penalty, though earnings face stricter limits.

Key Takeaways

  • Traditional 401(k) contributions reduce your taxable income in the year you make them, but withdrawals are taxed as ordinary income at your current tax rate.
  • Roth 401(k) contributions are made with after-tax dollars, but may have access to withdrawals in retirement are completely tax-free.
  • Withdrawing from a traditional 401(k) before age 59½ usually triggers a 10 percent early withdrawal penalty on top of income tax.
  • You must begin taking required minimum distributions from a traditional 401(k) at age 73, and those withdrawals are fully taxable.

How traditional 401(k) taxes work at contribution and withdrawal

When you contribute to a traditional 401(k), your employer deducts the money from your paycheck before calculating federal income tax. This means your W-2 form shows a lower gross income, which can put you in a lower tax bracket and reduce the total tax you owe that year. The money grows tax-free inside the account — you do not pay taxes on investment gains while the money sits there.

The tax bill comes due when you withdraw. Every dollar you take out is taxed as ordinary income at whatever your tax rate is in that year. If you withdraw $50,000 in a year when you are in the 22 percent tax bracket, you owe $11,000 in federal income tax on that withdrawal (before state taxes, which vary by location). The entire withdrawal is taxable, including both the money you originally contributed and all the investment gains.

Your employer will withhold taxes from 401(k) withdrawals automatically, usually at a default rate of 20 percent for lump-sum distributions. This withholding is an estimate — you may owe more or less when you file your tax return, depending on your total income that year and your actual tax bracket.

How Roth 401(k) taxes work at contribution and withdrawal

A Roth 401(k) contribution comes from your paycheck after taxes have already been taken out. Your employer still deducts the money from your pay, but it does not reduce your taxable income for the year. This means you pay income tax on the full amount of your salary, even the portion going into the Roth account.

The payoff comes at withdrawal. If you have held the Roth 401(k) for at least five years and you are age 59½ or older, you can withdraw the entire balance — contributions and all investment gains — completely tax-free. You receive the money with no federal income tax owed, no state income tax (in most states), and no tax forms to file related to that withdrawal.

If you withdraw before meeting both conditions (five years and age 59½), the rules split between contributions and earnings. You can always withdraw your own contributions tax-free and penalty-free. Earnings withdrawn early are taxed as ordinary income and hit with the 10 percent early withdrawal penalty, the same as a traditional 401(k).

Early withdrawal penalties and exceptions

Withdrawing from a traditional 401(k) before age 59½ triggers a 10 percent penalty on the amount withdrawn, in addition to income tax. A $20,000 early withdrawal would cost you $2,000 in penalty alone, plus income tax on the full $20,000. The penalty applies to the entire withdrawal unless you meet a narrow list of exceptions.

The IRS allows penalty-free early withdrawals in specific situations: substantially equal periodic payments (a complex calculation that locks you into regular withdrawals for five years or until age 59½, whichever is longer), withdrawals due to disability, withdrawals to pay medical expenses that exceed 7.5 percent of your adjusted gross income, and withdrawals to pay health insurance premiums while unemployed. Some plans also allow loans instead of withdrawals, which lets you borrow from your own balance and repay it with interest.

Roth 401(k) early withdrawals are more flexible for contributions but stricter for earnings. You can withdraw contributions at any time without penalty or tax. Earnings withdrawn before age 59½ and before five years of account ownership face both the 10 percent penalty and income tax, with the same narrow exceptions as traditional accounts.

Required minimum distributions and taxes

Starting at age 73, you must withdraw a minimum amount from a traditional 401(k) each year, whether you need the money or not. This amount is calculated by dividing your account balance by a life expectancy factor set by the IRS — the older you are, the larger the percentage you must withdraw. The IRS publishes updated tables each year, and your plan administrator can calculate the exact amount you owe.

Every dollar of a required minimum distribution is taxed as ordinary income. If your required minimum distribution is $30,000 and you are in the 24 percent tax bracket, you owe $7,200 in federal income tax on that withdrawal. The distribution is mandatory — if you miss it or withdraw less than required, the IRS charges a penalty of 25 percent of the shortfall (reduced to 10 percent if you correct it within two years).

Roth 401(k) accounts do not require minimum distributions during the account owner's lifetime. This is one significant tax advantage of Roth accounts in retirement, since you can leave the money untouched and let it grow tax-free for as long as you live. After your death, beneficiaries must take distributions, but the rules depend on their relationship to you and when you died.

State income taxes on 401(k) withdrawals

Federal income tax is only part of the tax bill. Most states also tax 401(k) withdrawals as ordinary income, at rates that vary widely. New York charges up to 6.85 percent, California up to 13.3 percent, and some states charge nothing. A few states — including Pennsylvania, Illinois, and Mississippi — do not tax retirement income at all, which can make a significant difference in your total tax bill.

Some states offer partial exemptions for retirement income. Tennessee and New Hampshire do not tax retirement income but do tax other types of income. Other states exempt only certain types of retirement accounts or only withdrawals after a certain age. Your state's tax treatment depends on where you live when you withdraw, not where you worked when you contributed.

How to estimate your tax bill on a 401(k) withdrawal

Your tax rate on a 401(k) withdrawal depends on your total income that year, not just the withdrawal amount. If you withdraw $40,000 from a traditional 401(k) in a year when you have no other income, your tax rate will be lower than if you withdraw the same amount in a year when you also have $100,000 in Social Security or pension income. This is why some people spread large withdrawals across multiple years — to keep each year's income lower and stay in a lower tax bracket.

You can use the IRS tax tables or a tax calculator to estimate your federal tax rate based on your total income. Add your state income tax rate to get the full picture. Remember that the withholding your plan takes out is just an estimate — you may owe more or less when you file your return. If you expect to owe a large amount, you can ask your plan to withhold extra, or you can make estimated tax payments throughout the year.

A tax professional can help you model different withdrawal strategies before you retire, showing you how much you would owe under different scenarios. This is especially useful if you have both traditional and Roth accounts, or if you have other sources of retirement income like Social Security or rental property.

Frequently Asked Questions

Can I avoid taxes on a 401(k) withdrawal by rolling it into an IRA?

A direct rollover to a traditional IRA does not trigger taxes — the money moves directly from the 401(k) to the IRA with no tax bill. If you take the money yourself and deposit it within 60 days, taxes are still avoided, but your plan will withhold 20 percent automatically. A rollover to a Roth IRA does trigger taxes on the full amount converted, since you are moving pre-tax money into an after-tax account.

Do I pay taxes on 401(k) investment gains while the money is still in the account?

No. Investment gains inside a 401(k) — whether traditional or Roth — are not taxed each year. You only pay taxes when you withdraw the money. This is one major advantage of 401(k) accounts: your money compounds without being reduced by annual investment taxes.

What happens to my 401(k) taxes if I move to a state with no income tax?

You pay state income tax based on where you live when you withdraw, not where you worked. If you move to Florida or Texas (which have no state income tax) and then withdraw from your 401(k), you owe no state income tax on that withdrawal. You still owe federal income tax regardless of where you live.

Is the 10 percent early withdrawal penalty the same for traditional and Roth 401(k)s?

The penalty is the same — 10 percent — but it applies differently. On a traditional 401(k), the penalty applies to the entire early withdrawal. On a Roth 401(k), the penalty applies only to earnings withdrawn early; contributions can always come out penalty-free. The exceptions to the penalty (disability, medical expenses, substantially equal payments) explore to both account types.

Do I have to pay taxes on a 401(k) loan?

No, as long as you repay the loan according to the plan's terms. A loan is not a withdrawal, so no taxes or penalties explore. If you leave your job before repaying the loan, any unpaid balance is treated as a withdrawal and becomes taxable and subject to the early withdrawal penalty if you are under 59½.