What Is an Employee Deferral in a 401(k)?
An employee deferral, also called an elective deferral or salary deferral, is money you choose to have withheld from your paycheck and deposited into your 401(k) instead of paid to you. Deferrals can be pre-tax or Roth, are capped at $24,500 for 2026, and are always 100% yours, immediately vested.
On this page
An elective deferral is compensation you elect to contribute to an employer plan rather than receive in cash. Pre-tax and Roth deferrals combined may not exceed $24,500 in 2026, plus $8,000 catch-up at age 50+ or $11,250 at ages 60–63. Deferrals are always 100% vested.
Source: IRC §402(g); IRS Notice 2025-67
If you have run into four different names for this and assumed they were four different things, you can relax. “Employee deferral,” “elective deferral,” “salary deferral,” and “salary reduction contribution” all mean exactly the same thing. Payroll systems and plan documents simply use different labels for the same paycheck deduction.
This is the most common way money enters a 401(k), and it is the piece you control completely. You pick the amount, you pick the tax treatment if your plan offers Roth, and you can change your mind during the year. Employer money, meaning the match and any profit sharing, is a separate contribution type that follows its own rules and its own limits.
What is the difference between a pre-tax deferral and a Roth deferral?
Both are elective deferrals and both draw on the same $24,500 limit for 2026. The only thing that changes between them is when you pay the tax.
- Pre-tax deferral: withheld before income tax, so it lowers your taxable income this year. The contribution and all its earnings are taxed as ordinary income when you withdraw them in retirement.
- Roth deferral: withheld after income tax, so there is no deduction now. In exchange, qualified withdrawals of the contribution and its earnings come out tax-free (IRC §402A). See the Roth 401(k) guide for the five-year rule and what makes a withdrawal qualified.
You do not have to pick one and stay there. You can split your deferrals between the two in any mix you want, say $15,000 pre-tax and $9,500 Roth, as long as the combined total stays inside the 402(g) limit.
One warning that trips people up. A Roth deferral is not the same thing as an after-tax (non-Roth) contribution, even though both are funded with money that has already been taxed. After-tax is a completely separate source that sits outside the $24,500 limit, and its earnings are taxable later unless you convert them.
The payroll election process
You make a deferral election, usually on your plan’s website or through HR, choosing either a percentage of pay or a flat dollar amount per paycheck. From there payroll takes over. It withholds that amount every pay period and deposits it into your 401(k), where it lands in whatever investments you selected.
A percentage election scales automatically with raises and bonuses, assuming your plan counts bonuses as eligible pay. A dollar election stays fixed until you change it yourself. Some plans offer only the percentage method, so your choice may already be made for you.
If you are aiming at the exact $24,500 maximum for 2026, the timing of your contributions matters as much as the total. Hitting the limit in September instead of December can cost you match dollars in the months you are no longer contributing, which is explained in detail on the match page.
How much per paycheck?
| Step | Your numbers |
|---|---|
| Your annual deferral target (the 2026 maximum is $24,500) | $_______ |
| Number of paychecks you will receive this year | _______ |
| Annual target divided by pay periods | $_______ per paycheck |
| Pay schedule | Pay periods per year | Per paycheck to reach $24,500 |
|---|---|---|
| Biweekly (every other Friday) | 26 | $942.31 |
| Semi-monthly (1st and 15th) | 24 | $1,020.83 |
| Monthly | 12 | $2,041.67 |
Divide your annual target by the number of paychecks you will actually get this year. Two cautions before you enter the number. First, if you are starting partway through the year, divide by the paychecks remaining, not by 26. Second, round down rather than up, because payroll stops your deferrals at the limit anyway and a rounded-up election just means your last check contributes less than you expected. If your plan only accepts percentages, divide the per-paycheck dollar figure by your gross pay per check to get the percentage to enter.
Can I change my 401(k) contribution anytime?
Under most plans, yes. You can raise, lower, or stop your deferral election whenever you want, and the change usually takes effect within one or two payroll cycles. Federal law only requires plans to allow election changes at least once per year, but nearly every modern plan is far more generous than that bare minimum.
Your plan document is what actually controls here, so check your summary plan description, the plain-language booklet your plan has to give you, or ask your administrator for the exact rule and the processing deadline for each payroll.
Stopping your deferrals carries no penalty of any kind. The money already in the account stays invested and keeps growing. You simply stop adding to it, and you stop earning any match during the months your deferral sits at zero, which is the real cost of pausing.
- ☐ Log in to your recordkeeper’s site (Fidelity, Empower, Vanguard, Principal, Voya, or whoever holds the plan) and find the page labeled “contributions” or “deferral election”
- ☐ Decide your annual target first, then work backward to the per-paycheck amount using the calculator above
- ☐ Choose your split between pre-tax and Roth, if your plan offers both
- ☐ Confirm the election is at least high enough to capture the full employer match
- ☐ Check whether your plan applies a separate election to bonus pay, because many do and a 0% bonus election quietly wastes a contribution opportunity
- ☐ If you are 50 or older, make sure the catch-up election is turned on as its own separate box
- ☐ Note the payroll effective date the site shows you, then verify the change on your next paystub
- ☐ Confirm the money is being invested rather than sitting in the plan’s default cash or money market option
Reading “deferral” on your paystub
A line labeled “401(k) deferral,” “401K EE,” “pre-tax 401k,” “Roth 401k,” or something similar shows the amount withheld from that check and sent to your plan. Pre-tax deferrals appear as a deduction that reduces your federal taxable wages. Roth deferrals reduce your net pay but leave your taxable wages alone.
Either way, deferrals are still subject to Social Security and Medicare (FICA) tax. This surprises people who expected a bigger paycheck bump. Deferring lowers your income tax, not your payroll tax.
Deferrals on your W-2
Your deferrals show up in box 12 of your W-2, with a different code for each type.
- Code D: pre-tax 401(k) elective deferrals.
- Code AA: designated Roth 401(k) deferrals.
Pre-tax deferrals are already excluded from the box 1 wage figure, which is why you never separately deduct them on your tax return. The tax break is baked into the W-2 before you ever see it.
The IRS matches those box 12 amounts against the 402(g) limit. If you worked two jobs in the same year, add up the code D and code AA amounts across every W-2 you received, because no single payroll system saw the combined total.
2026 deferral limits
The 402(g) limit for 2026 is $24,500, and it covers pre-tax and Roth deferrals combined across all of your 401(k) and 403(b) plans (IRS Notice 2025-67). On top of that ceiling, catch-up contributions add up to $8,000 at age 50 and above, or $11,250 at ages 60–63.
There is one more ceiling that often bites before the IRS one does. Your employer may cap deferrals at a percentage of pay, and that plan-level limit is perfectly legal. The full stack of limits is laid out in 401(k) contribution limits for 2026.
| Gross pay per check | $3,076.92 |
| 10% pre-tax deferral to the 401(k) | −$307.69 |
| Federal taxable pay | $2,769.23 |
| Federal income tax saved this check (22% × $307.69) | $67.69 |
| Net paycheck reduction | $240.00 |
Immediate vesting, by law
Your own deferrals, both pre-tax and Roth, are 100% vested from the moment they hit the account. That is federal law, not a favor from your employer, and no vesting schedule can ever be applied to them.
What this means in practice is simple. If you quit tomorrow, every dollar you deferred goes with you, along with everything those dollars earned. Vesting schedules reach only employer contributions, which is a different question covered in how 401(k) vesting works.
Automatic enrollment under SECURE 2.0
You may be deferring right now without ever having filled out a form. Under SECURE 2.0 §101, most 401(k) plans established after December 29, 2022 must automatically enroll eligible employees starting in 2025. The default deferral rate falls between 3% and 10% of pay, and it escalates by one percentage point per year until it reaches at least 10%.
Plans that existed before that date can use automatic enrollment voluntarily, and many do. You are never stuck with the default, because you can always opt out entirely or change the rate to whatever you want. The practical step is to look at your paystub for a deferral you do not remember choosing, then adjust the election to the number you actually intend.
Frequently asked questions
What does elective deferral mean on a 401(k)?
It means the contribution happened because you elected it. This is money you chose to have withheld from your pay and put into the plan, rather than money your employer added on its own. “Elective deferral,” “employee deferral,” and “salary deferral” are interchangeable terms for exactly the same contribution.
Is a Roth deferral the same as a Roth IRA contribution?
No. A Roth deferral goes into your 401(k) through payroll and counts against the $24,500 plan limit for 2026. A Roth IRA is a separate account you open and fund yourself, with its own $7,500 limit for 2026 and its own income-based eligibility rules. Nothing stops you from doing both in the same year.
What is a good deferral percentage?
At an absolute minimum, defer enough to capture your full employer match, because leaving match money behind is a guaranteed loss. Beyond that, the common rule of thumb is 10–15% of pay including the match, adjusted for your age, your income, and how late you got started.
Do employee deferrals reduce Social Security wages?
No. Pre-tax deferrals reduce your federal income tax wages but not your FICA wages. You still pay Social Security and Medicare tax on the deferred amounts, and the good news is that those wages still count toward your future Social Security benefit.
Can I defer 100% of my paycheck?
Only if your plan allows it, and even then payroll must still withhold FICA taxes and other deductions first, so the real maximum lands somewhat below 100%. Many plans cap elections at a percentage such as 75% or 90% of pay. You also cannot defer more than $24,500 for 2026, plus catch-up if you are eligible, no matter what percentage you enter.
Do deferrals stop automatically when I hit the limit?
Within a single employer, yes. Payroll systems stop 401(k) withholding once you reach $24,500 for 2026, continuing only the catch-up if you are eligible for it. Across two employers it works differently, because neither payroll system can see the other one’s numbers. That combined total is yours to track, or you end up with an excess deferral to unwind.
Related reading
- The 402(g) limit: $24,500 for 2026, excess-deferral fixes, year-by-year table
- Roth 401(k): how it works and when it beats pre-tax
- How the employer match works, and how to capture all of it
Sources: IRS: 401(k) contribution limits · IRS Notice 2025-67 (2026 limits) · IRC §402(g) · IRS: designated Roth account FAQs