The quickest way to find out exactly what kind of 401(k) you have is to check your Summary Plan Description, a document your employer is legally required to give you. It spells out the plan’s official name, type, contribution rules, and vesting schedule. If you never received one or can’t find it, your HR department or plan administrator can provide a copy. Beyond that, a few clues from your pay stubs, account statements, and employer type can help you narrow it down right now.
Where to Find Your Plan Type
Every employer-sponsored retirement plan has a Summary Plan Description (SPD). This document lists the name and type of plan, eligibility requirements, how contributions are calculated, what benefits you’re entitled to, and how to file a claim if something goes wrong. New employees must receive a copy within 90 days of becoming covered by the plan. If yours is buried in an old onboarding packet, ask HR or your benefits coordinator for a current version.
Your quarterly or annual account statement from the plan provider (Fidelity, Vanguard, Empower, Schwab, etc.) also typically labels the account by plan type. Log in to your account online and look for language like “Traditional 401(k),” “Roth 401(k),” “SIMPLE 401(k),” or even “403(b)” or “457(b).” The distinction matters because each plan type has different contribution limits, withdrawal rules, and tax treatment.
Search Your Employer’s Federal Filings
Most retirement plans with participants must file Form 5500 annually with the Department of Labor, and those filings are public. You can search them at the DOL’s EFAST2 online tool. Type your employer’s name or EIN into the search box, and you’ll find filings that identify the plan type, total assets, and number of participants. The search is case-insensitive, and you can use an asterisk as a wildcard if you’re not sure of the exact plan name. Click the arrow next to a result to download a ZIP file containing the PDF filing. This is especially useful if you’ve left a former employer and no longer have easy access to HR.
Traditional 401(k)
This is the most common type. You contribute pre-tax dollars from your paycheck, which lowers your taxable income now. The money grows tax-deferred, and you pay income tax when you withdraw it in retirement. For 2026, the employee deferral limit is $24,500. If you’re 50 or older, you can contribute additional catch-up amounts on top of that.
Employers can match your contributions, but they’re not required to. If your employer does match, the formula varies widely: some match dollar for dollar up to a percentage of your salary, others match 50 cents on the dollar, and some don’t match at all. Your SPD will spell out the exact formula and any vesting schedule (how long you need to work before the employer’s contributions are fully yours).
Roth 401(k)
A Roth 401(k) isn’t a separate plan. It’s an option within a traditional 401(k) plan that your employer may or may not offer. If your plan includes a Roth option, you can contribute after-tax dollars. You don’t get a tax break today, but qualified withdrawals in retirement are completely tax-free. The same $24,500 deferral limit for 2026 applies across your traditional and Roth contributions combined.
Check your pay stub or plan account. If you see “Roth 401(k)” deductions, your contributions are going in after tax. If you see “401(k)” or “pre-tax 401(k),” they’re traditional. Some people split contributions between both, and your account dashboard will show separate balances for each.
SIMPLE 401(k)
If you work for a small business, you might have a SIMPLE 401(k). This plan is designed for employers with fewer employees who want a simpler administrative setup. The biggest tell is the contribution limit: the employee deferral cap for SIMPLE plans is $17,000 for 2026, significantly lower than the $24,500 standard 401(k) limit. If your plan caps your contributions well below the standard limit, that’s a strong signal.
Another distinguishing feature is that your employer is required to contribute. They must either match your contributions dollar for dollar up to 3% of your pay, or make a flat 2% contribution for every eligible employee regardless of whether you contribute. No other employer contributions are allowed. In a standard 401(k), employer matches are optional and can follow almost any formula the company chooses.
It Might Not Be a 401(k) at All
Some people refer to their workplace retirement account as a “401(k)” when it’s actually a different plan type. The rules, limits, and withdrawal options differ, so it’s worth knowing which one you have.
If you work for a public school, hospital, or tax-exempt nonprofit, your plan is likely a 403(b). It works similarly to a 401(k) with the same 2026 deferral limit of $24,500, but the investment options sometimes lean more toward annuity contracts rather than mutual funds.
If you work for a state or local government, you likely have a 457(b) plan. State and local governments generally cannot offer 401(k) plans (with narrow exceptions for plans adopted before May 1986). A 457(b) has the same deferral limit as a 401(k), but one major difference: withdrawals before age 59½ are not subject to the 10% early withdrawal penalty that applies to 401(k) and 403(b) plans. That flexibility can matter if you retire or leave government work early.
Your employer type is the fastest clue. Private, for-profit company? Almost certainly a 401(k). Nonprofit or school? Probably a 403(b). Government? Likely a 457(b). Your account statement or SPD will confirm it.
What to Do Once You Know
Identifying your plan type unlocks a few practical decisions. First, check whether you’re hitting the right contribution limit. Plenty of people under-contribute because they assume the cap is lower than it is, or they’re confused about whether catch-up contributions apply to them. Second, find out if your plan offers a Roth option you haven’t been using. Third, look at your employer match: if you’re not contributing enough to capture the full match, you’re leaving free money on the table.
If you have accounts from past employers and aren’t sure what type they are, the same steps apply. Pull up old statements, contact the former employer’s HR department, or search the DOL’s Form 5500 database by company name. Knowing your plan type helps you decide whether to leave the money where it is, roll it into your current employer’s plan, or move it to an IRA.