You pay taxes on 401(k) money when you withdraw it, not when you contribute it — but the timing and rate depend on the type of account

A traditional 401(k) lets you put money in before taxes are taken out of your paycheck. That means you do not pay federal income tax on those contributions or the growth inside the account. When you withdraw the money — whether at retirement or earlier — you pay ordinary income tax on the full amount you take out. The tax is calculated at your regular income tax rate for that year, not a special rate.

A Roth 401(k) works the opposite way. You contribute money that has already been taxed. The money grows tax-free inside the account. When you withdraw it in retirement, you pay no tax on the original contributions or the earnings, as long as you follow the withdrawal rules. If you withdraw earnings before age 59½, you may owe taxes and a 10 percent penalty on the earnings portion only.

Your employer may also match your contributions. Matching money goes into a traditional 401(k) account, which means it is taxed when you withdraw it, regardless of whether your own contributions were traditional or Roth.

Key Takeaways

  • Traditional 401(k) withdrawals are taxed as ordinary income at your current tax rate, whether you take the money at retirement or before.
  • Roth 401(k) withdrawals are tax-free in retirement if you follow the rules, but early withdrawals of earnings trigger taxes and a 10 percent penalty.
  • Your employer's matching contributions are always taxed when withdrawn, even if your own contributions were Roth.
  • Withdrawals before age 59½ from a traditional 401(k) usually trigger a 10 percent early withdrawal penalty on top of income tax.

How traditional 401(k) taxes work

When you contribute to a traditional 401(k), your employer reduces your taxable income for that year. If you earn $60,000 and contribute $7,000 to a traditional 401(k), you only report $53,000 as income on your tax return. This lowers the federal income tax you owe that year.

The money inside the account grows without being taxed each year. If your balance grows from $50,000 to $75,000, you do not owe tax on that $25,000 gain while it sits in the account. The tax is deferred — it comes later, when you withdraw.

Once you withdraw money, the full amount you take out counts as income for that year. If you withdraw $10,000, you add $10,000 to your taxable income. Your employer withholds a percentage (usually 20 percent for 401(k) withdrawals) and sends it to the IRS, but you may owe more or less depending on your total income that year.

How Roth 401(k) taxes work

Roth 401(k) contributions come from your paycheck after taxes are already taken out. You do not get a tax deduction in the year you contribute. The money grows tax-free inside the account, and withdrawals in retirement are tax-free as long as the account has been open for at least five years and you are age 59½ or older.

If you withdraw money before age 59½, the rules split the withdrawal into two parts: your contributions and the earnings. You can withdraw your contributions tax-free at any time. The earnings portion is taxed as ordinary income, and you owe a 10 percent penalty on the earnings unless an exception applies (such as disability or a may have access to hardship).

Roth 401(k)s do not have required minimum distributions at age 73 like traditional 401(k)s do. This means you can leave the money untouched longer if you do not need it, and it continues to grow tax-free.

Early withdrawal penalties and exceptions

If you withdraw from a traditional 401(k) before age 59½, you owe income tax on the amount plus a 10 percent early withdrawal penalty. A $10,000 withdrawal might result in $2,000 withheld for taxes (20 percent) plus $1,000 in penalty, leaving you $7,000. You may owe additional tax when you file your return if your total income pushes you into a higher tax bracket.

Some situations allow you to withdraw without the 10 percent penalty, though you still owe income tax. These include disability, medical expenses that exceed 7.5 percent of your adjusted gross income, health insurance premiums while unemployed, and substantially equal periodic payments (a complex calculation that requires professional guidance). A few plans also allow loans instead of withdrawals, which you repay to your own account.

Roth 401(k) early withdrawals of earnings face the same 10 percent penalty and income tax, but you can always withdraw your contributions penalty-free.

Tax withholding and what you actually owe

When you request a 401(k) withdrawal, your plan administrator withholds taxes automatically. For lump-sum distributions, the standard withholding is 20 percent. For periodic distributions (regular monthly or annual payments), withholding depends on what you claim on a W-4P form — you can request more or less withholding, though you cannot request zero.

The amount withheld is not the same as the tax you actually owe. If you withdraw $50,000 and 20 percent is withheld ($10,000), but your tax rate for the year is 24 percent, you will owe an additional $2,000 when you file your return. If your rate is 15 percent, you will receive a refund of $2,500.

This is why it is important to plan withdrawals with your total income in mind. A large withdrawal in one year might push you into a higher tax bracket, increasing your rate on all your income that year.

Rollovers and transfers to avoid taxes

If you leave a job or retire, you can move your 401(k) balance to an Individual Retirement Account (IRA) or to your new employer's plan without paying tax or penalty. This is called a rollover. Your old plan sends the money directly to the new account, and no withholding occurs because no taxable event has happened.

A direct rollover (plan to plan) is the safest method. If your old plan sends you a check instead, you have 60 days to deposit it into an IRA or new plan account, or the full amount becomes taxable income. Even if you deposit it on time, your old plan will withhold 20 percent, and you must come up with that 20 percent from another source to deposit the full amount and avoid taxes.

Rollovers preserve the tax-deferred status of traditional 401(k) money. If you roll a traditional 401(k) into a Roth IRA, that conversion is a taxable event — you owe income tax on the full amount converted in that year.

Required minimum distributions and taxes

Starting at age 73, you must withdraw a minimum amount from a traditional 401(k) each year, calculated by dividing your account balance by a life expectancy factor set by the IRS. These required minimum distributions (RMDs) are taxed as ordinary income. If you do not take the full RMD, you owe a 25 percent penalty on the amount you failed to withdraw (10 percent if you correct it within two years).

Roth 401(k)s do not require distributions during your lifetime, but your beneficiaries will face RMD rules after you pass away. This is one reason some people convert traditional 401(k) balances to Roth accounts before RMDs begin — it eliminates the forced withdrawals and the associated taxes.

State and local taxes on 401(k) withdrawals

Federal income tax is not the only tax on 401(k) withdrawals. Most states with an income tax also tax 401(k) distributions at your state rate. A few states — including Florida, Texas, and Wyoming — do not tax income at all, so residents of those states owe no state tax on withdrawals. Other states offer partial exemptions for retirement income, but the rules vary widely.

If you retire in one state but withdraw from a 401(k) in another, you may owe tax to both states depending on where the plan is based and where you live. This is a situation where a tax professional can save you money by structuring withdrawals strategically.

Frequently Asked Questions

Do I pay taxes on 401(k) contributions?

Traditional 401(k) contributions are not taxed when you contribute — you get a tax deduction that year. Roth 401(k) contributions are made with after-tax money, so you do not get a deduction. Both types are taxed when you withdraw the money.

What if I need money before retirement?

You can withdraw from a traditional 401(k) at any time, but you owe income tax plus a 10 percent penalty if you are under 59½, unless an exception applies. From a Roth 401(k), you can withdraw your contributions anytime tax-free, but earnings withdrawals before 59½ trigger taxes and penalty. Some plans offer loans as an alternative.

Can I avoid taxes by rolling my 401(k) to an IRA?

A direct rollover from a 401(k) to a traditional IRA is not a taxable event — no tax is owed. If the plan sends you a check, you have 60 days to deposit it into an IRA to avoid taxes, but the plan withholds 20 percent upfront. Converting to a Roth IRA is taxable in the year of conversion.

How much tax will I owe on a withdrawal?

The tax depends on your total income that year and your tax bracket. A $20,000 withdrawal might result in $3,000 to $6,000 in federal tax depending on your other income, plus state tax if your state taxes income. Your plan withholds 20 percent, but you may owe more or less when you file your return.

Do I have to pay taxes on employer matching contributions?

Yes. Employer matching money goes into a traditional 401(k) account and is taxed when you withdraw it, regardless of whether your own contributions were traditional or Roth. The match is not taxed when it is deposited — only when you take it out.