401(k) vs Roth IRA: the names hide several separate decisions

A 401(k) and a Roth IRA differ in more than tax treatment. One comes through an employer and the other is opened by an individual. They have separate contribution limits, different eligibility rules, and usually different investment menus. A worker may be allowed to use both in the same year.

The comparison gets muddled because "401(k)" describes an account provided through work, while "Roth" describes a tax treatment. A workplace plan can offer both traditional and Roth 401(k) contributions. This guide uses a traditional 401(k) for the main comparison, then explains where a Roth 401(k) fits.

For 2026, the IRS set the employee 401(k) deferral limit at $24,500 and the combined traditional and Roth IRA contribution limit at $7,500. Those limits do not compete with each other. Putting money in one does not reduce the federal limit for the other, though income, compensation, and plan rules still apply.

The basic difference

Traditional 401(k) contributions generally come out of pay before federal income tax. They reduce current taxable income, and withdrawals are generally included in taxable income later. Payroll taxes can still apply to the contributed wages.

Roth IRA contributions use money that has already been taxed. They do not create a deduction. Qualified withdrawals can be free of federal income tax if the applicable rules are met.

That creates a timing question rather than a promise of "tax-free" money. A traditional contribution delays income tax. A Roth contribution pays tax before the money enters the account. The better after-tax result depends in part on the tax rates that apply at contribution and withdrawal, plus the amount actually saved and invested.

The Roth vs Traditional Calculator can compare simplified current and future tax-rate assumptions. It cannot predict future tax law or reproduce every feature of either account.

2026 contribution limits are not close

The IRS 2026 retirement limits announcement lists these amounts:

  • The standard employee 401(k) deferral limit is $24,500.
  • A participant age 50 or older can generally make an $8,000 catch-up contribution if the plan allows it.
  • Ages 60 through 63 have a higher 401(k) catch-up limit of $11,250 for 2026.
  • The combined limit across traditional and Roth IRAs is $7,500.
  • The IRA catch-up limit for someone age 50 or older is $1,100.

A person under 50 who is eligible for both could therefore contribute as much as $24,500 through a 401(k) and $7,500 across IRAs in 2026. That is $32,000 of combined employee contributions, before any employer money. This is a limit example, not a suggested savings target.

Splitting a 401(k) contribution between traditional and Roth does not double the $24,500 allowance. The same is true for IRAs: a contribution to a traditional IRA and a Roth IRA shares one $7,500 limit in 2026.

Employer contributions do not use the employee's $24,500 deferral allowance. They generally count toward the broader defined contribution plan limit, which is $72,000 for 2026 before catch-up contributions. The existing 401(k) contribution limits guide covers the overall cap and multiple-job rules in more detail.

The employer match can change the comparison

A Roth IRA has no employer match. A 401(k) may have one, but the formula, timing, and vesting rules come from the plan.

Suppose a plan adds 50 cents for each dollar an employee contributes, up to 6% of pay. That formula is not the same as a flat 3% contribution, even though both can reach the same maximum employer amount in a simple example. Some plans calculate the match every paycheck. Others provide a year-end true-up. Employer money may also vest over time, which means part of it can be forfeited when someone leaves before satisfying the plan's service requirement.

The 401(k) Match Calculator estimates a basic matching formula. The plan's summary plan description controls the actual result.

This is why comparing only the account tax labels can miss a large part of the compensation package. A match is employer-provided money, but it is not always immediately owned and it may not arrive in the way a quick calculator assumes.

Roth IRA income limits can block a direct contribution

An eligible employee can generally make traditional 401(k) deferrals without a Roth-style income phaseout, subject to plan participation and nondiscrimination rules. Direct Roth IRA contributions do have income limits.

For 2026, the IRS says the Roth IRA contribution phaseout is:

  • $153,000 to $168,000 of modified adjusted gross income for single filers and heads of household.
  • $242,000 to $252,000 for married couples filing jointly.
  • $0 to $10,000 for married individuals filing separately when the restrictive rule applies.

Within a phaseout range, the permitted direct contribution is reduced. At or above the top of the range, a direct Roth IRA contribution is generally unavailable. Filing status and the IRS definition of modified adjusted gross income matter, so ordinary gross pay is not enough to settle eligibility.

An IRA contribution also requires eligible compensation under the tax rules. A 401(k), meanwhile, requires access to an employer plan and enough eligible pay to defer. The federal maximum is not a guarantee that every person can contribute that amount.

A Roth 401(k) is a third option, not another IRA

If a workplace plan offers a designated Roth account, an employee can direct some or all 401(k) deferrals there. Roth 401(k) contributions are made after tax, but they still use the 401(k) employee limit rather than the IRA limit. There is no Roth IRA income phaseout for participating in the designated Roth side of a 401(k).

A worker could use a traditional 401(k), a Roth 401(k), and a Roth IRA in the same year if eligible. The traditional and Roth 401(k) deferrals share the $24,500 employee limit. The Roth IRA has its separate $7,500 IRA limit.

This distinction fixes a common but consequential misunderstanding: choosing a Roth 401(k) does not consume Roth IRA contribution room, and opening a Roth IRA does not create extra 401(k) room.

Investment choice and account control differ

A 401(k) uses the funds, brokerage window, and service providers selected by the employer. A strong plan may offer low-cost diversified funds and institutional pricing. A weak one may have a narrow menu or added administrative expenses. Participants cannot simply move an active account to any provider they prefer while remaining in the same plan.

A Roth IRA is opened with a bank, brokerage, or other eligible custodian. The owner chooses the provider and generally has a wider range of investments. Wider choice can reduce costs, but it can also make it easier to buy concentrated, expensive, or unsuitable products. The tax label does not make the investments safe.

Fees deserve a direct comparison. Look at fund expense ratios, plan administration charges, advisory fees, trading costs, and any fee tied to leaving a former employer's plan. A small annual percentage can matter over a long holding period.

Withdrawal rules are not interchangeable

Traditional 401(k) withdrawals are generally taxable. A distribution before age 59 1/2 may also face a 10% additional tax unless an exception applies. Plans can impose their own distribution procedures, and a 401(k) loan is available only if the plan permits one.

A Roth IRA has separate ordering and qualification rules. IRS Publication 590-B explains how Roth IRA distributions are assigned among regular contributions, conversions, and earnings. Regular contributions generally come out before earnings, but that does not make every withdrawal consequence-free. Conversion timing, earnings, age, and the reason for a distribution can change the tax result.

For Roth earnings to come out as part of a qualified distribution, the five-year rule must be satisfied along with a qualifying event such as reaching age 59 1/2, disability, death, or an eligible first-home distribution within the statutory limit. The five-year clock is easy to oversimplify, especially when conversions and workplace Roth money are involved.

Treating a retirement account as emergency cash can also interrupt compounding. The Retirement Savings Calculator shows how contribution amounts and time affect a simplified projection, although actual market returns will not arrive at a constant rate.

Required distributions depend on the tax side of the account

The IRS required minimum distribution FAQ says traditional 401(k) accounts are generally subject to required minimum distributions beginning at age 73. A current employee may be able to delay distributions from that employer's plan until retirement, unless the employee is a 5% owner.

Roth IRAs do not require distributions while the original owner is alive. Designated Roth 401(k) accounts also no longer require lifetime distributions from the owner under current rules. Beneficiaries face a separate set of distribution requirements.

The lack of an owner RMD can make a Roth IRA useful in estate and withdrawal planning, but beneficiary rules, taxes, and account goals still need to be considered together. It is not a reason to ignore fees or investment risk.

A cleaner way to compare the accounts

Start with facts that do not require a tax forecast:

1. Confirm whether the employer offers a 401(k), a match, and a Roth contribution option. 2. Read the match formula, vesting schedule, fees, and investment menu. 3. Check Roth IRA eligibility using filing status and modified adjusted gross income. 4. Compare the separate 2026 contribution limits rather than treating the accounts as substitutes. 5. Test several current and retirement tax-rate assumptions instead of relying on one prediction. 6. Review withdrawal and RMD rules for the exact account type.

The accounts can work alongside each other. A 401(k) offers payroll contributions, much more employee contribution room, and a possible employer match. A Roth IRA offers individual control, a separate contribution allowance, and no lifetime RMD for the owner. Which features matter most depends on the plan, taxes, fees, and intended use of the money.

Browse the Economy section for more retirement, tax, inflation, and rate explainers.

Educational only. This article provides general information, not personalized financial, investment, tax, legal, or retirement advice.

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