The choice between pre-tax and Roth 403(b) contributions comes down to one question: is your tax rate higher today, or will it be higher when you retire? Pre-tax contributions lower your tax bill now and are taxed on the way out, so they win when your current bracket is higher than your future one. Roth contributions are taxed now and come out tax-free later, so they win when today’s rate is the bargain. If you can’t confidently predict which will be higher, the IRS lets you split contributions between both within the same plan, and many savers should.
How Each Option Is Taxed
A 403(b) is a retirement plan for employees of public schools, churches, and organizations exempt under Section 501(c)(3) of the Internal Revenue Code, including hospitals, charities, and certain schools.1Internal Revenue Service. IRC 403(b) Tax-Sheltered Annuity Plans Every dollar you contribute goes into one of two tax buckets, and you can use both.
Pre-tax contributions come out of your paycheck before federal income tax is calculated. Earn $70,000, contribute $10,000 pre-tax, and your taxable income for the year is $60,000. The full $10,000 goes into the account and grows untaxed. Every dollar you eventually pull out in retirement is taxed as ordinary income, both your contributions and the growth on them.2Internal Revenue Service. Retirement Plans FAQs Regarding 403(b) Tax-Sheltered Annuity Plans
Roth contributions go in after taxes are withheld. The same $10,000 contribution costs you more out of pocket in the current year because you’ve paid your full tax bill first. In exchange, qualified withdrawals come out completely tax-free, including years of investment growth.3Internal Revenue Service. Retirement Topics – Designated Roth Account To qualify, you must hold the Roth account for at least five tax years (the year of your first Roth contribution counts as year one) and meet one of these conditions: reach age 59½, become disabled, or the distribution goes to a beneficiary after your death.4Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts The legal framework for designated Roth contributions sits in 26 U.S.C. § 402A.5Office of the Law Revision Counsel. 26 U.S. Code 402A – Optional Treatment of Elective Deferrals as Roth Contributions
If you withdraw Roth earnings before those conditions are met, the earnings are taxed and may face a 10% penalty. Your original Roth contributions, however, are never taxed again because you already paid tax on that money going in.3Internal Revenue Service. Retirement Topics – Designated Roth Account
When Pre-Tax Wins
Pre-tax makes more sense when your tax rate today is meaningfully higher than the rate you’ll pay in retirement. For 2026, a single filer earning roughly $106,000 to $202,000 lands in the 24% federal bracket. Married couples filing jointly hit 24% between about $211,000 and $404,000. If you expect a modest retirement income that keeps you in the 10% or 12% bracket, every pre-tax dollar you contribute avoids 24% taxation now and only faces 10% or 12% later. That gap compounds over decades.
The underlying math is simple. If your tax rate stays exactly the same from now through retirement, pre-tax and Roth produce identical after-tax wealth. The advantage only shows up when the rates differ. Someone in the 32% or 37% bracket today who retires into the 22% bracket keeps a larger share of every dollar by deferring. Pre-tax contributions also reduce your adjusted gross income in the year you make them, which can help you qualify for other tax benefits that phase out at higher incomes.
The risk is that you’re betting on future tax rates you don’t control. If Congress raises rates, or if your retirement income turns out higher than expected because of pensions, Social Security, and required withdrawals from other accounts, you may end up in the same bracket or higher. Pre-tax savers have no way to undo that exposure once the money is in the account.
When Roth Wins
Roth makes more sense when your current rate is low relative to what you’ll face later. A single filer earning under about $50,000 in 2026 sits in the 12% bracket. Paying 12% now to lock in tax-free growth and tax-free withdrawals for life is a strong deal for someone early in their career whose income will climb. If that person eventually retires in the 22% or 24% bracket, they’ve paid far less than the distributions would have cost.
Roth contributions also hedge against legislative risk. U.S. tax rates are relatively low by historical standards, and no one knows what brackets will look like in 2050. Roth money is immune to that uncertainty because you’ve already settled with the IRS.
There’s a separate Roth advantage that often gets overlooked: required minimum distributions. Pre-tax 403(b) balances force you to start withdrawing at age 73 whether you need the money or not, and the IRS imposes an excise tax of 25% on any shortfall, dropping to 10% if you correct it within two years.6Internal Revenue Service. Retirement Topics – Required Minimum Distributions (RMDs) Starting with the 2024 tax year, Roth balances in 403(b) plans are no longer subject to required minimum distributions during the account owner’s lifetime, matching the long-standing Roth IRA treatment.7Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs The Roth balance can keep growing tax-free for the rest of your life. For pre-tax savers, forced withdrawals at 73 can push you into a higher bracket and increase how much of your Social Security is taxed.
One more thing about Roth balances: a $500,000 Roth 403(b) is genuinely worth $500,000 in retirement spending. A $500,000 pre-tax 403(b) is worth less because taxes still need to come out. People tend to underestimate how much of a pre-tax balance actually belongs to the IRS.
Splitting Between Both
You don’t have to choose one bucket. The IRS lets you split contributions between pre-tax and Roth within the same 403(b), as long as your combined total stays within the annual limit. Doing both gives you tax diversification in retirement: a pool of pre-tax money you draw from in low-income years, and a pool of Roth money you tap when extra income would push you into a higher bracket.
That flexibility becomes a real lever year by year. If you have a year with high medical expenses and want to keep your adjusted gross income down, you pull from the Roth side. If you’re comfortably in a low bracket with room to spare, you draw from pre-tax. A common approach is contributing Roth during lower-earning years and shifting toward pre-tax as your salary climbs into higher brackets.
What Changes for High Earners in 2026
For the 2026 tax year, the combined pre-tax and Roth elective deferral limit is $24,500.8Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Workers 50 and older can add an $8,000 catch-up, and workers ages 60 through 63 get a higher $11,250 catch-up under the SECURE 2.0 Act.9Internal Revenue Service. Retirement Topics – 403(b) Contribution Limits
A rule change kicks in starting in 2026 that removes the pre-tax vs Roth choice for higher-paid catch-up contributors. If you earned $150,000 or more in FICA-taxable wages during 2025, any catch-up contributions you make in 2026 must go into a Roth account. Regular contributions up to $24,500 are unaffected and can still be pre-tax. The threshold is based on the prior year’s W-2 wages, not the current year’s income. If your plan doesn’t offer a Roth option, you won’t be able to make catch-up contributions at all until the plan adds one.
How Employer Matches Are Treated
Employer matching contributions don’t count against your $24,500 elective deferral limit. Most employers still deposit their match as pre-tax money, which means even if 100% of your own contributions are Roth, the employer’s portion sits in a pre-tax bucket and will be taxable when you withdraw it in retirement.
The SECURE 2.0 Act now permits plan sponsors to offer Roth matching. If your employer designates the match as Roth, you must include that match amount in your taxable income for the year it’s contributed, and the employer reports it on Form 1099-R rather than your W-2.10Internal Revenue Service. SECURE 2.0 Act Changes Affect How Businesses Complete Forms W-2 Few plans have adopted this yet, but the option exists for savers who want their entire 403(b) balance to be Roth.