Traditional vs Roth 401(k) and IRA: How to Choose

Almost every retirement plan today offers two flavors: traditional (pre-tax) and Roth (after-tax). They have the same limits and invest the same way. The only real difference is when you pay the tax. This guide explains each, shows the 2026 limits and gives you a simple way to decide.

How each one is taxed

The IRS states it plainly for the Roth IRA: you cannot deduct contributions to a Roth IRA, and if you satisfy the requirements, qualified distributions are tax-free. It also says you can leave amounts in your Roth IRA as long as you live. IRS Publication 590-B explains what makes a distribution qualified.

The 2026 limits

The IRS announced these limits for 2026:

The 401(k) limit applies to what you contribute in total across traditional and Roth in the plan. The IRA limit is for all your IRAs together.

Income limits

There is no income limit on a Roth 401(k). A Roth IRA does have one. For 2026, the ability to contribute to a Roth IRA phases out between these amounts of modified adjusted gross income:

• Single or head of household: $153,000 to $168,000.
• Married filing jointly: $242,000 to $252,000.

For a traditional IRA, anyone with earned income can contribute, but whether you can deduct the contribution depends on your income if you are covered by a workplace plan. The 2026 deduction phase-outs are $81,000 to $91,000 for a single filer covered by a plan, and $129,000 to $149,000 for a married couple filing jointly when the contributing spouse is covered. A spouse who is not covered, but whose partner is, faces a phase-out of $242,000 to $252,000.

A worked example

You are in the 22% federal bracket and want to put $6,000 into retirement this year. Assume the money grows 7% a year for 30 years, so each dollar becomes about $7.61.

Case 1: your tax rate stays at 22%

• Traditional: $6,000 goes in before tax. It grows to about $45,700. You pay 22% when you take it out, leaving about $35,600.
• Roth: $6,000 of pay is $4,680 after 22% tax. That $4,680 goes in, grows to about $35,600 and comes out tax-free. You end with about $35,600.

The two are the same, because the same 22% is paid once in each case, either at the start or at the end. The "trick" is to compare equal amounts of take-home pay. The Roth person puts in only $4,680 because $1,320 went to tax. The traditional person puts in $6,000 and has that $1,320 in the account instead.

Case 2: your rate falls to 12% in retirement

The traditional account leaves about $40,200 after tax (88% of $45,700). The Roth leaves about $35,600. Traditional wins by about $4,600.

Case 3: your rate rises to 32%

The traditional account leaves about $31,100 after tax. The Roth still leaves about $35,600. Roth wins by about $4,600.

So the whole decision is a bet about whether your tax rate in retirement will be below or above your rate today.

How to decide

Traditional tends to fit when:

• You are in a high bracket now and expect to be in a lower one in retirement.
• You want the deduction to lower your tax bill this year, or to qualify for something that depends on your income.

Roth tends to fit when:

• You are early in your career with a low bracket and expect your income, and your taxes, to rise.
• You want tax-free money in retirement and no tax surprise on withdrawal.
• You want more flexibility, because Roth IRA money can be left to grow for as long as you live.

A split often works when you are not sure. Putting some in each type gives you a mix of taxable and tax-free money later, so you can choose which to draw on each year. This is sometimes called tax diversification.

What about the employer match?

Take the employer match first. It is free money and it beats almost any other choice, which is why most guides tell you to contribute at least enough to get the full match. Check your plan's rules for how matching dollars are treated, since many plans put the match in a pre-tax account even if your own contributions are Roth, while some plans can place it in a Roth account.

Savers who earn a low income

If your income is modest, the Saver's Credit may reduce your tax bill when you contribute to a retirement plan. For 2026 the income limit is $80,500 for married couples filing jointly, $60,375 for heads of household and $40,250 for single filers and married filing separately. The size of the credit shrinks as income rises. Because it is a credit, it works with both traditional and Roth contributions.

The retirement savings calculator projects what a savings rate, an employer match and a return can grow to. Use it to see how much a yearly contribution could be worth in today's dollars.

Common mistakes

• Skipping the match. Leaving it unclaimed is the most common and costly mistake.
• Contributing to a Roth IRA when your income is too high. An excess contribution can bring a penalty. Check the phase-out amounts each year.
• Cashing out when you change jobs. This can mean tax and a penalty. Roll the money into the new plan or an IRA instead.
• Choosing without a plan. Ask what your tax bracket is today and what you expect later, then write it down.

Frequently asked questions

Can I have both a traditional and a Roth account?

Yes. You can contribute to both, as long as the total stays within the limits. For example, you could put $4,000 into a Roth IRA and $3,500 into a traditional IRA in 2026, for $7,500 in total.

Is a Roth always better for young people?

Often, but not always. A young worker in a low bracket gains from paying tax now at a low rate. If the bracket is already high, the deduction can be worth more.

Do Roth withdrawals count toward Social Security tax?

Qualified Roth withdrawals are not part of your taxable income, so they do not add to the taxable part of your Social Security benefits. That is one reason people value Roth money in retirement.

What happens to the match in a Roth 401(k)?

It depends on the plan. Many plans put the employer match in a pre-tax account. Ask your plan administrator.

How do I know which tax bracket I am in?

Look at your last tax return, or use the tax bracket calculator on this site. The 2026 brackets and standard deduction come from the IRS.

The bottom line

Traditional saves tax now. Roth saves tax later. If you expect your tax rate to be the same, either works. If you think it will be lower in retirement, lean traditional. If you think it will be higher, lean Roth. If you are not sure, use both, and always take the full employer match.

Sources

• 401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500, Internal Revenue Service
• Roth IRAs, Internal Revenue Service
• Retirement topics: IRA contribution limits, Internal Revenue Service
• Retirement topics: 401(k) and profit-sharing plan contribution limits, Internal Revenue Service

The growth example (7% a year for 30 years, equal take-home cost) is an illustration, not a prediction. Tax rules for retirement accounts have many details, so check the IRS publications or a tax professional for your situation. Last reviewed October 12, 2026.