Yes, you can add money to your 401(k), but only through payroll deductions from your paycheck or by rolling in funds from another retirement account. You cannot write a check or transfer money from your bank account directly into the plan. For 2026, you can defer up to $24,500 of your own wages, and your employer may add matching contributions on top of that.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Why It Has to Come Out of Your Paycheck
A 401(k) is a payroll-based account by design. The tax treatment exists because your employer withholds a portion of your wages before you receive them and sends that money directly to your plan’s investment account. Federal law ties contributions to earned compensation, so personal savings, inheritance, or funds sitting in checking are not eligible.
The practical effect is that your annual contribution is limited by what you earn and how many pay periods remain in the year. If you decide in July to max out your 401(k), you have roughly half the year to fit the full amount into your remaining paychecks. Some plans let you defer a flat dollar amount per pay period rather than a percentage of salary, which makes it easier to hit an exact annual total.
How Much You Can Contribute in 2026
The IRS caps your own elective deferrals at $24,500 for 2026, up from $23,500 in 2025.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 The same cap applies to 403(b) and most 457 plans. It’s an aggregate limit, so if you change jobs partway through the year, your combined contributions to both employers’ plans cannot exceed $24,500.2Office of the Law Revision Counsel. 26 USC 402 – Taxability of Beneficiary of Employees Trust
Employer matching does not count against this $24,500 personal cap.3Internal Revenue Service. Matching Contributions Help You Save More for Retirement The match sits in a separate bucket alongside your deferrals under a larger overall ceiling, discussed below. The deferral limit adjusts periodically for inflation, so check the current figure each fall when the IRS releases the next year’s numbers.
Extra Room If You’re 50 or Older
If you turn 50 at any point during the calendar year, you can defer beyond the standard limit. The general catch-up contribution for 2026 is $8,000, which brings your total possible deferral to $32,500.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Even a December 31 birthday qualifies you for the full amount that year. Catch-up dollars come out of your paycheck the same way as regular contributions; you just set a higher deferral rate.
Ages 60 Through 63 Get Even More
Starting in 2026, SECURE 2.0 introduces a larger catch-up for participants who are 60, 61, 62, or 63 during the calendar year. Instead of the standard $8,000, these workers can defer an additional $11,250, for a combined maximum of $35,750.1Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 The window closes at 64, when you drop back to the regular $8,000 catch-up.
Roth Catch-Up for High Earners
Beginning with the 2026 tax year, catch-up contributions must be designated as Roth if your wages from the plan sponsor exceeded $150,000 in the prior year.4Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living Your 2025 wages determine whether your 2026 catch-up dollars go in pre-tax or Roth. If you earned $150,000 or less in 2025, you can still choose either. The threshold is indexed for inflation. If your plan doesn’t currently offer a Roth option, the IRS has indicated it must add one so affected employees can still make catch-up contributions, so confirm with your employer that the plan has been updated.
Pre-Tax or Roth: Same Limit, Different Tax Timing
Most plans let you split contributions between two types. Pre-tax (traditional) contributions reduce your taxable income now, but every dollar you withdraw in retirement is taxed as ordinary income. Roth 401(k) contributions work in reverse: you pay income tax on the money now, and qualified withdrawals in retirement, including investment gains, come out tax-free. A withdrawal is qualified if the account has been open at least five years and you’re at least 59½, disabled, or deceased.5Internal Revenue Service. Roth Comparison Chart
The $24,500 cap applies to both types combined. You can split contributions in any proportion, but the total cannot exceed the annual limit. Younger workers in lower brackets often lean Roth; higher earners closer to retirement often prefer the immediate deduction of pre-tax deferrals.
Employer Matching
Employer matching is money the company adds to your account on top of what you defer. A common formula is 50 cents on the dollar up to a set percentage of pay. If your employer matches 50% of contributions up to 5% of pay and you earn $60,000, contributing at least $3,000 (5%) captures the full $1,500 match.3Internal Revenue Service. Matching Contributions Help You Save More for Retirement
Matching contributions don’t reduce your own $24,500 deferral limit.3Internal Revenue Service. Matching Contributions Help You Save More for Retirement They grow tax-deferred and get taxed only at withdrawal. At minimum, aim to defer whatever percentage of your salary captures the full match.
One timing note: your employer isn’t required to deposit the match on the same schedule as your payroll deferrals. The law gives employers until their tax-filing deadline, including extensions, to make the deposit.6Internal Revenue Service. 401(k) Plan Fix-It Guide – You Haven’t Timely Deposited Employee Elective Deferrals Some plans match every pay period; others deposit a single lump sum after year-end. If your employer matches annually and you leave mid-year, you could lose part of the match, so check your plan’s rules.
After-Tax Contributions Above the $24,500 Cap
Some plans allow a third type of contribution: after-tax dollars beyond your regular deferral cap. These are not the same as Roth contributions, because earnings on after-tax money are taxable at withdrawal unless converted. The overall 2026 ceiling for everything going into your account, including your deferrals, employer match, and after-tax contributions combined, is $72,000 or 100% of your compensation, whichever is less.4Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living Catch-up contributions sit on top of this overall limit.
The main reason to bother with after-tax contributions is the “mega backdoor Roth” strategy: if your plan permits both after-tax contributions and either in-plan Roth conversions or in-service withdrawals, you can move those dollars into a Roth account. Only the earnings portion of the conversion triggers income tax, and converting quickly leaves little growth to tax. Not every plan supports this. Confirm with your administrator before assuming it’s available.
Rolling In Money From Another Retirement Account
A rollover is the one way to add money to your 401(k) that doesn’t come out of your paycheck. You can roll funds from a previous employer’s 401(k), a 403(b), a governmental 457(b), or a traditional IRA into your current plan’s pre-tax account.7Internal Revenue Service. Rollover Chart If the plan has a designated Roth account, it can also accept rollovers from a Roth IRA or another plan’s Roth account.
Your plan is not required to accept rollovers, so ask first. A direct rollover, where the old plan sends the funds straight to the new one, avoids tax withholding. If the distribution is paid to you instead, you have 60 days to deposit it into the new plan, and the old plan will typically withhold 20% for taxes. You get the withheld amount back when you file your return, but you have to cover that 20% from other funds to roll over the full balance.8Internal Revenue Service. Rollovers of Retirement Plan and IRA Distributions
Consolidating old accounts into your current 401(k) can simplify management and sometimes gives access to lower-cost institutional funds. The trade-off is a narrower investment menu than you’d find in an IRA.
Changing How Much You Contribute
Adjusting your deferral is usually a five-minute task on your employer’s benefits portal or the plan administrator’s site. Log in, find your retirement plan settings, and enter a new percentage or dollar amount. Many plans also let you schedule automatic annual increases so your rate rises by 1% each year without any action on your part.
Changes typically take one to two pay cycles to appear. Check your next pay stub to confirm the new withholding. If you’re trying to hit $24,500 and you started late in the year, divide the remaining room by the paychecks left and set your deferral accordingly. Some plans automatically cap per-paycheck deferrals so you can’t exceed the annual limit; others don’t, so track the math yourself.
If You Contribute Too Much
If your total elective deferrals across all 401(k) plans exceed $24,500, you need to pull the excess out before April 15 of the following year. You notify the plan of the overcontribution, and the plan distributes the excess plus any earnings on it. Those earnings are taxed in the year distributed.2Office of the Law Revision Counsel. 26 USC 402 – Taxability of Beneficiary of Employees Trust
Miss the April 15 deadline and the excess gets taxed twice: once in the year you contributed it, and again when you withdraw it in retirement. The most common cause is changing jobs mid-year and deferring into two plans without adding up the totals. If that describes you, contact the second employer’s plan administrator early in the new year to request a corrective distribution.