401(k) vs. 403(b) vs. 457(b) vs. TSP: 2026–2027 Contribution Limits Compared

If you’ve ever had a 401(k) at one job and a 403(b) at the next, you’ve probably wondered whether the IRS treats them as the same thing. Mostly, yes — 401(k), 403(b), and TSP plans all share one combined $24,500 employee deferral limit for 2026.

The exception is the 457(b), and it’s a bigger exception than most people realize.

The $24,500 Limit Is Shared — Except for One Plan Type

The IRS calls this the Section 402(g) aggregate limit, and it applies across every 401(k), 403(b), and TSP account you personally contribute to in a calendar year, no matter how many employers issued them. Two different 401(k)s in the same year from a job change? Still one shared $24,500 cap.

Governmental 457(b) plans don’t fall under that aggregate limit. The IRS explicitly carves them out — a 457(b) has its own, completely separate $24,500 limit in 2026.

That means a public school teacher with a 403(b) and a state-offered governmental 457(b) can defer up to $24,500 into each — $49,000 total — in the same year. I see this trip up a lot of nonprofit and government employees who assume all their retirement accounts share one pool, the way 401(k)s and 403(b)s do.

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401(k) vs. 403(b): What Actually Differs

For most workers, the practical difference between a 401(k) and a 403(b) comes down to who’s offering it, not the tax mechanics. 401(k)s are the default at private, for-profit employers. 403(b)s show up at nonprofits, public schools, hospitals, and religious organizations.

The contribution limits, catch-up rules, and Roth options are essentially identical between the two. Where they can diverge is investment menu — 403(b)s have historically leaned on annuity products with higher fees, though most modern plans now offer low-cost mutual funds and ETFs too.

One 403(b)-only perk worth knowing: employees with 15+ years at a qualifying nonprofit or school may be eligible for an additional catch-up contribution on top of the standard age-50 catch-up. I cover the mechanics of that 15-year rule, along with every other catch-up scenario across plan types, in my full catch-up contribution guide.

If your employer offers a straightforward 401(k) with no 403(b)/457(b) complexity, my 401(k)-specific contribution and catch-up breakdown walks through employer match, vesting, and automatic enrollment in more depth than I can fit here.

457(b): Governmental vs. Non-Governmental — A Real Difference

Not all 457(b) plans are created equal, and this is the part I see glossed over most often.

Governmental 457(b) plans — offered by state and local government employers — get the separate $24,500 limit described above, and the money sits in a trust that’s protected from the employer’s creditors, just like a 401(k) or 403(b).

Non-governmental 457(b) plans — sometimes called “top-hat” plans — are offered by certain tax-exempt organizations (think large nonprofits, hospital systems) to a select group of executives or highly compensated employees. These are legally structured as unsecured promises to pay, not trust assets. If the employer goes bankrupt, participants in a non-governmental 457(b) are treated as general creditors, right alongside anyone else the company owes money to.

That’s a meaningfully different risk profile from a 401(k) or governmental 457(b), and it’s worth understanding before you defer a large chunk of compensation into one. See the IRS’s own explanation of 457(b) plan rules for the full distinction.

One upside 457(b)s do offer, governmental or not: no 10% early withdrawal penalty after you separate from service, regardless of age. That’s different from a 401(k) or 403(b), where early withdrawals before 59½ usually trigger the penalty on top of ordinary income tax.

TSP: The Federal Employee’s Version

The Thrift Savings Plan is the federal government’s version of a 401(k), and it runs on the same $24,500 employee limit and the same catch-up rules for 2026.

A few things make TSP distinct. Federal employees under FERS get an automatic 1% agency contribution regardless of whether they contribute anything themselves, plus a match on the first 5% they defer. TSP also uses a “spillover” method for catch-up contributions — once you hit the regular $24,500 limit, eligible contributions automatically start counting as catch-up instead, with no separate catch-up election needed. See the TSP’s own 2026 contribution limit bulletin for the official figures and fund-specific details.

401(a) Isn’t the Same as 401(k)

If you work for state or local government, you may have a 401(a) plan instead of — or alongside — a 401(k). The names look similar, but they work differently.

A 401(a) is typically a mandatory, employer-designed plan where the contribution rate (often a fixed percentage of salary) is set by the employer, not chosen freely by the employee. Some public employers use 401(a) plans for their base retirement contribution and then offer a voluntary 401(k) or 457(b) on top for additional savings. If your pay stub shows a “401a” deduction you didn’t sign up for, that’s very likely what’s happening.

Example — Priya, stacking a 403(b) and a governmental 457(b): Priya works at a public hospital system that offers both a 403(b) and a state governmental 457(b). She’s 45 and wants to save aggressively. Because the two plans don’t share the 402(g) limit, she can defer $24,500 into her 403(b) and $24,500 into her 457(b) — $49,000 total for 2026 — well beyond what a single-401(k) private-sector worker could put away.

Example — Marcus, comparing TSP to his old private-sector 401(k): Marcus just left a private-sector job with a standard 401(k) and 4% match for a federal position with TSP access. His new elective deferral limit is the same $24,500, but TSP adds an automatic 1% agency contribution he gets regardless of his own deferral, plus a match on his first 5% — richer than the 4% match he had before, even before he contributes a dollar of his own.

What About IRAs, SIMPLE IRAs, and SEP-IRAs?

Everything above covers employer-sponsored plans. IRAs run on a completely separate limit — $7,500 for 2026, plus a $1,100 catch-up if you’re 50+ — and that limit doesn’t interact with your 401(k), 403(b), 457(b), or TSP deferrals at all. You can max out a 401(k) and still fund a full Traditional or Roth IRA on top of it, subject to the usual Roth income limits.

If you work for a small business instead of a large employer, you may have a SIMPLE IRA rather than a 401(k) — it runs on its own, lower limit structure. And if you’re self-employed with no employees, a SEP-IRA works on a percentage-of-compensation formula that doesn’t resemble any of the plans above. For the full combined picture across every account type, my 401(k)/IRA/Roth IRA hub ties all of these together in one place.

Looking Ahead: 2027 Outlook

The IRS typically confirms next year’s limits in late October or early November, after the third-quarter inflation data is finalized — expect an announcement around November 1, 2026. Milliman’s latest inflation-based forecast projects the shared $24,500 limit rising to roughly $25,000 for 401(k), 403(b), TSP, and governmental 457(b) plans alike, since all four are indexed the same way under Section 402(g)-related rules.

These are estimates, not official numbers, and they can move if inflation data comes in higher or lower than expected between now and the announcement. I’ll update this page — and the table above — the moment the IRS makes it official.

Common Issues to Watch Out For

I get versions of these questions constantly from readers juggling more than one plan type.

Assuming a 457(b) shares your 401(k)/403(b) limit. It doesn’t, if it’s governmental. This is the single biggest misunderstanding I see among teachers, nonprofit staff, and government workers with access to both — and it means a lot of people are under-saving relative to what they’re actually allowed to defer.

Confusing a mandatory 401(a) deduction with a voluntary 401(k). If your paycheck shows a 401(a) contribution you don’t remember electing, that’s almost certainly a mandatory employer plan, not something you can adjust like a 401(k) deferral rate.

Not checking whether a 457(b) is governmental or non-governmental. The tax treatment looks similar on paper, but the creditor protection is not. If you’re deferring a meaningful amount into a non-governmental “top-hat” 457(b), understand that it’s an unsecured promise from your employer, not money held safely in a trust.

Forgetting the 402(g) limit is per person, not per plan, when you switch jobs. If you have two 401(k)s or a 401(k) and a 403(b) in the same calendar year from different employers, your new employer’s plan has no way of knowing what you already contributed elsewhere. Track it yourself — the correction process for going over is the same excess-contribution headache regardless of which plan type caused it.

Assuming TSP catch-up needs a separate election. It doesn’t anymore. TSP’s spillover method automatically routes contributions above the regular limit into catch-up status once you’re eligible, so you don’t need to fill out a second form.