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The difference comes down to when you pay income tax. With a traditional 401(k), you skip the tax now and pay it when you withdraw. With a Roth 401(k), you pay the tax now and generally withdraw qualified money tax-free later.
Most beginners get stuck on one question. Which version will leave them better off? Honestly, nobody can answer that for certain, because the answer depends on tax rates decades from now.
This guide compares the two side by side. It covers the tax math, the income-limit difference, the shared 2026 limits, employer match rules, and withdrawals. If you are new to workplace plans, start with What Is a 401(k)? first.
Quick Answer
- Traditional contributions reduce your taxable income now. Withdrawals are generally taxed as ordinary income later.
- Roth contributions are taxed now. Qualified withdrawals, including earnings, are generally tax-free.
- Both share one 2026 employee contribution limit of $24,500. You can split it between the two in any proportion, if your plan offers both. Catch-up rules add a Roth requirement for some higher-paid workers.
- Roth 401(k) contributions have no income limit. However, your employer’s plan must offer the option.
Traditional 401(k) vs. Roth 401(k) at a Glance
The table below summarizes the main differences. Details for each row follow in the sections after it.
| Feature | Traditional 401(k) | Roth 401(k) |
|---|---|---|
| Tax on contributions | Pre-tax; lowers taxable income now | After-tax; no deduction now |
| Tax on withdrawals | Generally taxed as ordinary income | Qualified withdrawals, including earnings, are tax-free |
| Income limit to contribute | None | None |
| 2026 employee limit (under 50) | $24,500 combined across both types | |
| Employer match | Generally pre-tax | Generally pre-tax; a Roth match is possible only if your plan offers it and you elect it |
| Lifetime required distributions for the owner | Yes, once the required age is reached (some plans allow a delay while you still work) | No |
| Availability | Offered by most 401(k) plans | Only if your plan adds the feature |
These are 2026 figures. Limits and rules change, so confirm the current numbers with the IRS before you adjust your paycheck deferral.
How the Tax Difference Works
Here is a simplified example. Suppose all of a $10,000 contribution falls in the 22% federal bracket. The example compares the same $10,000 contribution for both types. It ignores state tax and investment growth.
- Traditional: The $10,000 comes out before income tax. Your federal tax falls by about $2,200, so your take-home pay drops by about $7,800.
- Roth: Your take-home pay drops by the full $10,000. You get no deduction now.
These two choices cost you different amounts of take-home pay. Payroll tax also works differently from income tax. Traditional deferrals generally still count as wages for Social Security and Medicare tax. To compare them at the same take-home cost, shrink the Roth contribution. Alternatively, invest the Traditional tax savings.
The tradeoff shows up later. The traditional balance is generally taxed when you withdraw it. The Roth balance, including growth, is generally tax-free if the withdrawal is qualified.
Therefore, the real question is simple. Will your tax rate on withdrawals be higher or lower than the rate you save today? If the two rates match, the simplified math comes out the same. That assumes the same pre-tax dollars, the same investment return, and no other tax effects. Nobody knows for sure, and tax law can change.
No Income Limit: A Key Difference From a Roth IRA
Many people confuse the Roth 401(k) with the Roth IRA. They share the same tax treatment, but their rules differ in important ways.
A Roth IRA phases out at higher incomes. Check Roth IRA Income Limits 2026 to see where you stand. A Roth 401(k) has no such limit, according to this IRS comparison of Roth IRAs and designated Roth accounts.
As a result, a high earner who cannot contribute directly to a Roth IRA may still choose Roth treatment at work. The catch is availability. Your employer must add a designated Roth feature to the plan.
The 2026 Contribution Limit Is Shared
The 2026 employee deferral limit is $24,500. It applies to your traditional and Roth contributions combined, not to each one separately. Employer contributions do not use up this limit. However, they count toward a separate overall limit on all contributions to your account.
For example, you could put $15,000 into the traditional side and $9,500 into the Roth side. According to the IRS, you can divide your deferrals in any proportion you choose, if the plan offers both.
Workers age 50 or older may add a catch-up contribution if the plan permits it. The catch-up is $8,000 for most participants and $11,250 for workers who turn 60 through 63 during the year. Certain higher-paid workers must make catch-up contributions on a Roth basis. 2026 401(k) Catch-Up Rules covers the wage threshold and plan requirements.
What Happens to Your Employer Match
Many beginners assume a Roth deferral earns a Roth match. Traditionally, that has not been true. According to the IRS, an employer must allocate the match on Roth deferrals into a pre-tax account.
That rule has loosened. Since SECURE 2.0, a plan may let employees elect to receive certain matching contributions as Roth. The match must be fully vested when it is allocated. Under IRS Notice 2024-2, the amount counts as income for the year it is allocated to your account. The plan reports it on Form 1099-R, and no federal income tax is withheld. As a result, you may need to adjust your withholding or make estimated payments.
Not every plan offers this option. Ask your plan administrator how your match is treated. Then read What Is a 401(k) Employer Match? to make sure you capture all of it.
Withdrawals and Required Distributions
A Roth 401(k) withdrawal is tax-free only if it is qualified. It needs two things. First, the five-year period must be complete. Second, the distribution must come after age 59½, because of disability, or after death.
For most taxpayers, the five-year count starts on January 1 of the year you first make a designated Roth contribution to that plan. It is not a 60-month count from your first paycheck. It is also separate from your Roth IRA clock. A direct rollover from another plan’s Roth account may carry over the earlier start date.
A nonqualified withdrawal is prorated between contributions and taxable earnings. The earnings part may also face the 10% early-distribution tax. This differs from Roth IRA ordering rules.
Required distributions are another difference. The IRS states that the RMD rules do not apply to designated Roth accounts while the owner is alive. Beneficiaries, however, remain subject to the rules. A traditional 401(k) is different, and Required Minimum Distributions Explained covers the deadlines and penalties.
Which One Fits You?
I like to frame this as a question about your tax bracket, not a prediction about the market. No choice is automatically better. Here are the situations where each side tends to fit.
- Roth may fit if you expect your tax rate on withdrawals to exceed the rate you would save today. It may also fit if you want tax-free money as a hedge against future tax changes.
- Traditional may fit if the deduction saves tax at a high rate today and you expect a lower rate later. It may also fit if you need to lower your taxable income now.
- A split may fit if you are unsure. Using both gives you tax diversification, so you rely less on one forecast.
Whichever side you choose, capture the full employer match first. How to Maximize Your 401(k) shows how to raise your contributions step by step.
Common Mistakes to Avoid
Assuming the Roth option exists. A plan must be amended to add designated Roth contributions. Therefore, check your plan documents before you plan around it.
Counting the limit twice. The $24,500 limit covers both types together. As a result, you cannot contribute that amount to each side.
Treating Roth as always better. Roth gives up a deduction today. Specifically, that tradeoff hurts most when your current bracket is high.
Mixing up the 401(k) and the IRA. The two have separate limits and separate rules. If you use both, track each limit separately.
Verify Before You Choose
Plan features differ from employer to employer. Therefore, confirm your options in your plan’s summary and in the IRS FAQs on designated Roth accounts. Confirm the current limits in the IRS announcement of 2026 retirement plan limits. A tax professional can help you compare the two against your own situation.
The Bottom Line
A traditional 401(k) gives you a tax break now. A Roth 401(k) gives you tax-free qualified withdrawals later. Both share one contribution limit, and neither has an income limit.
If you cannot decide, a split is a reasonable starting point. Revisit the mix as your income and your plan change.
For the full order of operations across all your accounts, see Retirement Accounts for Beginners.
FAQ
A. No. The IRS states that the designated Roth contribution limit is not affected by filing status or adjusted gross income. However, your employer’s plan must offer the Roth option.
A. Yes, if your plan offers both. You can split your deferrals in any proportion. However, the combined total cannot exceed the 2026 limit of $24,500, plus any catch-up the plan permits. Some higher-paid workers must make their catch-up contributions as Roth.
A. Usually not. The match is generally pre-tax. Some plans let you elect a Roth match, but it must be fully vested when allocated. It is generally taxed in the year it is allocated. Ask your plan administrator.
A. According to the IRS, the RMD rules do not apply to designated Roth accounts while the owner is alive. Beneficiaries, however, are subject to RMD rules.
Disclaimer: Tax limits and rules change from year to year. Confirm current amounts with the IRS, your plan administrator, or a qualified tax professional before choosing between a traditional and a Roth 401(k).