To know whether your 401(k) is a Roth or a traditional account, look in four places: your most recent pay stub, your W-2, your plan’s online portal, and your Summary Plan Description. The label is the giveaway. Traditional 401(k) contributions come out of your paycheck before income taxes; Roth 401(k) contributions come out after tax.1Internal Revenue Service. Roth Comparison Chart That single difference drives how your account is tagged everywhere it appears.
Check Your Pay Stub First
Open your latest pay stub and find the deductions section. Payroll systems name the two contribution types differently, and the name is usually all you need.
A Roth deduction appears as “Roth,” “Roth 401(k),” or “Designated Roth.” A traditional deduction shows as “401(k),” “Pre-Tax 401(k),” or “Pre-Tax Deferral” with no Roth label.2Internal Revenue Service. Common Errors on Form W-2 Codes for Retirement Plans If you see both lines, your plan lets you split contributions and each portion is tracked separately. If what you see doesn’t match what you expected to be contributing, raise it with HR or payroll quickly, because misrouted contributions get harder to untangle the longer they sit.
Don’t Mistake After-Tax Voluntary for Roth
Some plans offer a third category called “after-tax voluntary” or “non-Roth after-tax.” Like Roth, these use money you’ve already paid tax on, but the earnings are taxed as ordinary income at withdrawal rather than tax-free. If your pay stub shows a line labeled “After-Tax” without the word “Roth” anywhere on it, that money is going into the non-Roth after-tax bucket, not a Roth account.
Check Your W-2 Box 12
Your Form W-2 is the most definitive record of what you contributed and how it was classified. Look at Box 12 and read the letter code next to the dollar amount:
- Code D means traditional pre-tax elective deferrals to a 401(k).
- Code AA means designated Roth contributions to a 401(k).
Code AA with a dollar amount tells you that you made Roth contributions during the year.3Internal Revenue Service. General Instructions for Forms W-2 and W-3 (2026) Code D alone means your contributions were entirely pre-tax. Both codes together means you split. Employers are required to report Roth contributions separately under Code AA, so this box is an official tax record of the account type.4Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
Check Your Plan’s Online Portal
Your plan’s recordkeeper (the brokerage your employer uses) runs an online dashboard that breaks down your balance by source. Log in and open the section labeled “Account Summary,” “Balance by Source,” or “Investment Details.” A Roth balance appears as its own line, usually “Roth Employee Contributions” or “Designated Roth,” separate from any traditional pre-tax balance. Quarterly statements show the same breakdown and give you a history of how each contribution was classified.
One thing often surprises people here. Your employer’s matching contributions may show up on a pre-tax line even when your own contributions are Roth. That’s standard: employers are required to place matching contributions into a pre-tax account unless the plan has specifically adopted a Roth match feature.5Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts So a single plan can hold a split balance: a pre-tax piece (the match) that will be taxed at withdrawal, and a Roth piece (your contributions and their earnings) that won’t. Seeing both does not mean you’re in the wrong account; it means the plan is doing what the rules require.
Check Your Summary Plan Description
If the first three checks leave you uncertain, the Summary Plan Description settles it. This is the governing document for your employer’s retirement plan, and federal law requires your employer to provide it to every participant in language an average employee can understand.6Office of the Law Revision Counsel. 29 U.S. Code 1022 – Summary Plan Description Find the section on contributions. It will say whether the plan includes a Roth elective deferral option alongside or instead of traditional pre-tax deferrals.
If the document doesn’t mention a Roth feature, the plan likely only accepts traditional pre-tax contributions, and whatever you’re contributing is pre-tax. Request the most recent version from HR, since plan administrators are required to update it when the plan’s structure changes. It’s the final word on both what the plan offers and whether you’re enrolled in the Roth side of it.
Why the Answer Matters: The Five-Year Rule
The reason to confirm your account type before you need the money is that Roth 401(k) withdrawals are only fully tax-free when they qualify as a “qualified distribution.” That takes two things at once:
- Five tax years must have passed since January 1 of the year you made your first Roth contribution to the plan.
- You must be at least 59½, become disabled, or the distribution must be made after your death to a beneficiary.
Both conditions have to be met.7Internal Revenue Service. Retirement Topics – Designated Roth Account The five-year clock starts on the first day of the tax year of your first Roth contribution, not the contribution date itself. A first Roth contribution in October 2026 starts the clock on January 1, 2026, and it runs through December 31, 2030. If you rolled a Roth balance in from a prior employer’s plan, the clock may start from the earlier plan’s first contribution date.5Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts
If you take Roth money out before both conditions are satisfied, your own contributions still come out tax-free because you already paid tax on them, but the earnings portion is taxed as ordinary income and may also face a 10% early withdrawal penalty. That’s the practical cost of guessing wrong about your account type, and it’s the reason the labels on your pay stub, W-2, portal, and plan document are worth reading closely now rather than at withdrawal.