The difference between a 403(b) and a 401(k) is mostly about who sponsors the plan, not how it treats your money. Both let you defer up to $24,500 in 2026, both offer traditional and Roth options, and both follow nearly identical withdrawal rules. A 401(k) is what private employers offer; a 403(b) is reserved for public schools, tax-exempt nonprofits, and churches. That single distinction drives every meaningful downstream difference: the investments you can pick, the fees you pay, the federal protections that apply, and one extra catch-up contribution that only 403(b) participants can use.
Who Can Offer Each Plan
Any for-profit business can sponsor a 401(k). It is the standard private-sector workplace retirement plan.
A 403(b) is limited to three types of employers: public schools (including state colleges and universities), organizations tax-exempt under Internal Revenue Code Section 501(c)(3), and churches or church-controlled organizations.1Internal Revenue Service. Retirement Plans FAQs Regarding 403(b) Tax-Sheltered Annuity Plans The 501(c)(3) category picks up hospitals, charities, museums, and private nonprofit schools.2Office of the Law Revision Counsel. 26 U.S. Code 501 – Exemption From Tax on Corporations, Certain Trusts, Etc.
You don’t pick between the two. Your employer’s tax status decides for you.
Contribution Limits Are Nearly Identical
The IRS applies the same elective deferral ceiling to both plans. In 2026, you can put in up to $24,500 of your own money, combining pre-tax and Roth.3Internal Revenue Service. Retirement Topics – Contributions If you’re 50 or older, you can add another $8,000 as a catch-up, taking you to $32,500.4Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living
Participants who turn 60, 61, 62, or 63 during the year get a higher “super catch-up” instead of the age-50 amount. In 2026 that figure is $11,250, pushing the ceiling to $35,750 for those four ages.5Internal Revenue Service. Retirement Topics – 403(b) Contribution Limits After 64 you revert to the standard $8,000. This super catch-up applies to both plan types.
The total annual additions limit, which combines your deferrals with any employer contributions, is $72,000 for 2026 under Section 415(c).4Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living Catch-up dollars sit on top of that cap. Same rule for both plans.
The One Real Difference: The 403(b) 15-Year Rule
If you’ve worked for the same eligible 403(b) employer for at least 15 years, you may be able to defer an extra $3,000 per year beyond the standard limit, capped at a $15,000 lifetime total with that employer.6Internal Revenue Service. 403(b) Plans – Catch-up Contributions Nothing equivalent exists in a 401(k).
The 15-year catch-up stacks with age-based catch-ups. The 15-year amount applies first, then the age-based amount fills the remaining room.5Internal Revenue Service. Retirement Topics – 403(b) Contribution Limits A 60-year-old with 15-plus years of eligible service could theoretically defer $38,750 in 2026 ($24,500 + $3,000 + $11,250). Your plan document has to allow the 15-year catch-up, and not every plan does. Check before you count on it.
Investments and Fees: Where Your Wallet Feels the Difference
A 401(k) usually offers a menu of mutual funds across asset classes, often with target-date funds and index funds, and sometimes a brokerage window for individual stocks and ETFs.
The 403(b) began life as a “tax-sheltered annuity” and that history shows. Many 403(b) plans still lean on annuity contracts, both fixed and variable, from insurance companies. Modern 403(b) plans have added mutual funds, but annuities remain common in a way they aren’t in 401(k) plans.
The fee gap can be substantial. According to a Government Accountability Office study cited in the source material, fees on 403(b) investment options ranged from 0.01% to 2.37%, with variable annuities averaging around 2.25% annually. Index mutual funds in many 401(k) plans, by contrast, carry expense ratios between 0.02% and 0.08%. Annuity contracts often add mortality and expense charges and surrender penalties on top.
Over a 30-year career, a 1% annual fee difference can shrink your ending balance by roughly a quarter. If your 403(b) is heavy on annuity products, look at whether the plan also offers lower-cost mutual funds. Some employers have moved their 403(b) lineups toward the fee levels you’d see in a good 401(k). Many haven’t.
ERISA Protections Depend on the Employer
The Employee Retirement Income Security Act sets fiduciary duties, reporting requirements, and participant protections for most workplace retirement plans. Nearly all 401(k) plans are covered. Most 403(b) plans sponsored by private nonprofits are covered too.
The exception is 403(b) plans sponsored by public schools, state universities, and churches. Those are exempt from ERISA entirely.7Congress.gov. 403(b) Pension Plans: Overview and Legislative Developments Fewer federal reporting rules apply, and participants have weaker recourse if something goes wrong administratively. Church plans can elect into ERISA coverage, but most don’t.
Church-sponsored 403(b) plans get further latitude: they can use “retirement income accounts” without the annuity-or-mutual-fund investment restriction that binds other 403(b) plans.7Congress.gov. 403(b) Pension Plans: Overview and Legislative Developments If you work for a religious organization, your plan may look meaningfully different from a public-university 403(b).
Withdrawals, Loans, and RMDs
The withdrawal rules are effectively the same across both plans.
Distributions before age 59½ generally trigger a 10% early withdrawal penalty on top of ordinary income tax.8Internal Revenue Service. Hardships, Early Withdrawals and Loans Roth contributions come out tax-free; Roth earnings pulled early are taxable and penalized unless an exception applies.
The Rule of 55 waives the 10% penalty if you leave your job during or after the year you turn 55, but only for withdrawals from that employer’s plan.9Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions Public safety employees at state or local governments get the same break starting at 50. Roll the money into an IRA and you lose this protection. This rule works identically for 401(k) and 403(b) plans.
Both plans can allow loans if the plan document permits them. The maximum loan is the lesser of $50,000 or 50% of your vested balance, typically repaid within five years.10Internal Revenue Service. Retirement Topics – Plan Loans If you leave the job with an outstanding loan and can’t repay it, the balance becomes a taxable distribution, plus the 10% penalty if you’re under 59½.8Internal Revenue Service. Hardships, Early Withdrawals and Loans
Required minimum distributions start at 73 if you were born between 1951 and 1959, and at 75 if you were born in 1960 or later.11Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs Both plans qualify for the “still working” exception: if you’re still employed by the plan sponsor and don’t own 5% or more of the business, you can delay RMDs from that plan until you actually retire. That exception doesn’t extend to old accounts at previous employers or to IRAs.
Designated Roth balances inside a 401(k) or 403(b) are now exempt from RMDs during the account owner’s lifetime, effective in 2024 under SECURE 2.0.11Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs Before that change, Roth 401(k) and Roth 403(b) balances had to be tapped even though Roth IRAs did not.
Employer Match and Vesting
Employer matching is standard in 401(k) plans and increasingly available in 403(b) plans, though many school district 403(b) plans historically offered no match. If your employer does match, its contributions count toward the $72,000 total but not toward your $24,500 deferral limit.
Your own contributions vest immediately in either plan. Employer contributions can vest over time. Federal law caps the schedule: three-year cliff vesting (0% until three years, then 100%) or six-year graded vesting (starting at 20% after two years, reaching 100% at six).12Internal Revenue Service. Retirement Topics – Vesting Same caps for both plans. If you’re weighing when to leave a job, look at the schedule first; leaving months early can cost thousands.
Rollovers Between the Plans
When you change jobs, you can move money from a 401(k) into a 403(b) or the other way, provided the receiving plan accepts rollovers.13Internal Revenue Service. Rollover Chart Both plans also roll into a traditional IRA with no tax consequences, or into a Roth IRA if you’re willing to pay income tax on the converted amount that year.
Use a direct trustee-to-trustee transfer. If the plan cuts you a check instead, it withholds 20% for federal taxes and you have 60 days to deposit the full amount into the new account, replacing that 20% out of pocket. Miss the deadline and the whole distribution becomes taxable, plus the 10% penalty if you’re under 59½.
Not every plan accepts every incoming rollover. Some older annuity-based 403(b) plans won’t take money from a 401(k). Confirm with both sides before starting the transfer.
What This Means When You’re Comparing Jobs
Since you don’t get to choose your plan type, the practical question is what to do with the plan you have.
If your 403(b) is dominated by annuity contracts with high fees, check whether the plan also offers mutual funds and shift where you can. Fund a Roth IRA on the side to keep some of your retirement money in a low-cost environment. If you’ve been with the same qualifying employer for 15-plus years, ask whether the plan allows the 15-year catch-up; it’s genuine extra room that 401(k) participants don’t get.
If you have a 401(k), your lineup and fees are more likely to be competitive, and your employer match is more likely to be generous. Contribute at least enough to capture the full match. The tax treatment is the same either way. The differences that actually move your ending balance are fees, match generosity, and, for long-tenured nonprofit and school employees, the 15-year rule.