Maxing Out Your 401(k) Early Can Cost You Employer Match Dollars, Unless Your Plan Has a True-Up (2026)
Maxing out your 401(k) early can shut off your employer match. See the 2026 numbers, how true-ups work, and the deferral rate that avoids the trap.
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Disclaimer: Informational only, not tax, legal, or financial advice. Plan terms govern and vary by employer. Rules and limits can change; check current IRS guidance, your Summary Plan Description, or consult a professional.
The Short Version
Most employers calculate your match per pay period, using only that check’s deferral against that check’s pay. If you front-load and hit the 2026 elective deferral limit of $24,500 in, say, October, your deferral drops to $0 for the rest of the year. Under a per-pay-period formula, your match drops to $0 with it.
Some plans fix that after year-end with a true-up. Many do not. Among employers that match more often than once a year, about a third stop the match and never true it up, according to the Plan Sponsor Council of America’s 68th Annual Survey of 401(k) Plans.
The difference is real money. In the worked example below, a $180,000 earner deferring 25% of pay forfeits $2,357.69 of match in a single year, purely from timing.
Why Maxing Out Early Can Cost You Match Dollars
A matching formula has two parts people usually notice (the percentage matched and the cap) and one part almost nobody reads: the computation period.
The computation period is the window of time the plan looks at when it applies the formula. Two plans can advertise the identical “50% of the first 6%” match and behave completely differently:
- Per payroll period. The formula applies only to the compensation and deferrals in that specific pay cycle. Defer nothing on a check, get nothing matched on that check. No memory, no carryover.
- Plan year (annual). The formula applies to total plan-year deferrals against total plan-year compensation. Timing within the year is irrelevant.
Under a plan-year computation, front-loading is invisible to the match. Under a payroll-period computation, front-loading is expensive, because your match is capped check by check and there is no mechanism to reach back and pay you for the checks where you deferred zero.
PSCA’s 68th Annual Survey found that 89% of surveyed employers make matching contributions more frequently than annually. Within that group: 25% keep matching all year even after the participant stops deferring, 38% stop the match and then perform a year-end true-up, and 34% stop the match with no true-up at all. That last third is the group this article is written for.
Note the nesting there. The 34% figure is a share of the employers who match more often than annually, not a share of all 401(k) plans. It is still a large number of people.
What a 401(k) True-Up Actually Is
A true-up is a single employer contribution made after the plan year closes. The plan recalculates what your match would have been if the formula had been applied to full-year pay and full-year deferrals, compares that to what it already deposited paycheck by paycheck, and funds the shortfall.
Newfront’s payroll compliance team uses a clean illustration: someone earning $100,000 with a 50% match on deferrals up to 6% of pay. A steady deferrer collects $3,000 across the year. Someone who defers nothing until July, then 12% for the back half, collects only $1,500 during the year, and a true-up deposits the missing $1,500 after year-end.
True-ups have been getting more common, though slowly. Deloitte’s Defined Contribution Benchmarking Survey found 54% of plan sponsors offering one, up from 45% in 2015. Better odds than a coin flip, and nowhere near a guarantee.
A few details matter:
Timing. True-ups are calculated after December 31, because that is the first moment the plan can see the full year. Most land between January and March. Some plans take until the employer’s corporate tax-filing deadline. Your Summary Plan Description states the schedule.
No investment gains. The true-up deposits the missing dollars, not the missing dollars plus what they would have earned. So even a plan with a true-up costs a front-loader some compounding, because match money that should have been invested in June arrives the following February instead. That cost is usually small, and far smaller than losing the match outright, but it is not zero.
Safe harbor plans have a floor. A safe harbor plan using a computation period shorter than the plan year must fund matching contributions at least quarterly. It does not eliminate the front-loading problem, but it does limit how long your money sits uninvested.
Worked Example: The Dollars You Forfeit
Take a $180,000 salary, paid biweekly across 26 checks, so $6,923.08 of gross per check. Assume a common formula, 50% of deferrals up to 6% of pay, computed per pay period, with no true-up. (This is an illustrative formula, not an industry average. Vanguard’s How America Saves 2026 reports that average employer contributions have climbed to a record 4.7% of pay, but formulas vary widely.)
The most this plan will match on any single check is 3% of that check: $207.69. Across 26 checks with steady deferrals, that is $5,400.00 a year.
Now set the deferral rate to 25% and watch what happens.
| Amount | |
|---|---|
| Deferral per check at 25% | $1,730.77 |
| Checks 1 through 14, full deferral | $1,730.77 each, $24,230.77 cumulative |
| Check 15, trimmed by payroll at the limit | $269.23, cumulative $24,500.00 |
| Checks 16 through 26 (11 checks) | $0 deferral, $0 match |
| Match earned, checks 1 through 14 | 3% of each check x 14 = $2,907.69 |
| Match earned, check 15 | $134.62 |
| Total match received | $3,042.31 |
| Full-year match if deferred evenly | $5,400.00 |
| Match forfeited | $2,357.69 |
Check 15 is worth a second look. The deferral there is $269.23, which is only 3.89% of that check’s gross, below the 6% cap. So the plan matches 50% of the whole thing rather than hitting the ceiling. After that, eleven checks pass with nothing deferred and nothing matched.
The same salary, same plan, deferring at the even rate instead: $5,400.00, the whole thing. Same $24,500 into the account either way. One version just costs $2,357.69 more.
Does this hit lower salaries too?
Less often, and that is the point worth internalizing: front-loading risk scales with income.
At $95,000 paid biweekly ($3,653.85 per check) with a 100% match on the first 4% of pay, the annual match is $3,800. To reach $24,500 at all, you have to defer about 26% of pay for the entire year, which lands you on the limit right at check 26. Nothing is forfeited.
Push that same person to a 40% deferral rate and the picture changes. They hit $24,500 on check 17, sit out the last nine checks, and collect $2,484.62 instead of $3,800. That is $1,315.38 left behind.
So the trigger is whether your rate multiplied by your pay hits the limit before your final paycheck of the year, not your salary by itself.
The Per-Paycheck Rate That Lands Exactly on the Limit
The fix is arithmetic, and it is short:
Even rate = annual deferral limit ÷ annual gross pay
At $180,000: $24,500 ÷ $180,000 = 13.61%. Set that and your last check of the year is the one that crosses the finish line, with a deferral on every check in between.
When payroll only accepts whole percentages
Plenty of payroll systems round to whole percents. Use a floor-and-top-off pattern: run the rounded-down rate for most of the year, then raise it for the final one or two checks.
For our $180,000 example, 13% for the first 24 checks contributes $900.00 per check, or $21,600.00. Bump to 21% for the last two checks ($1,453.85 each, $2,907.69 total) and payroll’s own hard stop at $24,500 trims the final check by a few dollars. Match collected: the full $5,400, because the deferral rate never drops below 6% on any check of the year.
What the two rates do to your actual check
The reason people front-load in the first place is that the annual number feels abstract while the paycheck number does not. Worth seeing both.
On that $6,923.08 biweekly gross, a 13% deferral pulls $900.00 out of the check. A 25% deferral pulls $1,730.77. That is $830.77 of difference per check, twenty-six times a year.
Your take-home does not swing by the full $830.77, though. A traditional deferral reduces the wages subject to federal income tax and most state income taxes, so part of the difference comes back as lower withholding. It does not reduce Social Security or Medicare, which are calculated on your original gross either way. The net effect depends on your bracket and your state, which is exactly the kind of comparison worth running before you commit to a rate for twelve months.
What breaks a naive calculation
An extra paycheck. Dividing by 26 assumes 26 checks. Some biweekly employees see 27 in certain calendar years, which quietly lowers the rate you need. We covered the mechanics in 27 paychecks in 2026.
Bonuses. If your bonus check has your normal deferral percentage applied to it, that money counts toward the same $24,500 limit and can pull your finish line months earlier than planned. Check whether your plan uses a separate bonus deferral election.
Mid-year raises. A raise raises your per-check gross, so a fixed percentage now contributes more per check than your original math assumed.
Mid-year correction
Arrived here in September having already over-deferred? Recalculate:
New rate = (limit minus year-to-date deferrals) ÷ (remaining checks × gross per check)
One guardrail. If the result comes out below the rate your match formula rewards (6% in our example), you are already over-deferred for the year, and the match loss on the remaining checks is locked in. In that case, set the rate to whatever preserves the match on the checks you have left and accept the smaller total deferral, unless a true-up makes the whole question moot.
Switching to Roth deferrals does not help here, by the way. Roth and traditional deferrals share the same $24,500 limit, so the match timing is identical. Roth vs. traditional 401(k) is a separate decision.
You can model any of this against your actual take-home with the 401(k) contribution calculator, and check where a rate change leaves you for the rest of the year with the year-end take-home projection calculator.
How to Find the True-Up Language in Your Plan Documents
You do not have to guess. Under ERISA, your plan administrator must provide you the Summary Plan Description free of charge. The Department of Labor calls it the document that tells participants what the plan provides and how it operates. If your administrator will not hand it over, DOL’s Employee Benefits Security Administration takes calls at 1-866-444-3272.
Open the PDF and search for these terms:
true-upandtrue up(both spellings)computation periodmatching contribution periodpayroll periodplan yearannual match
Then read the sentence around the hit. The distinction you are looking for is whether the match is determined on each payroll period or on compensation for the plan year. Plan-year language usually means you are covered even without the phrase “true-up” appearing anywhere. Payroll-period language with no true-up paragraph is the risky combination.
A couple of phrasings are easy to misread. “Matching contributions are allocated each payroll period” describes when the money is deposited, not necessarily how it is calculated, so keep reading. “The matching contribution is determined on the basis of compensation for the plan year” is the sentence you want.
The actual election lives in the plan’s Adoption Agreement, which the SPD summarizes. If the SPD is ambiguous, that is the document to ask about.
If you would rather just ask, here is a message you can paste to HR or benefits:
Is our 401(k) match computed per payroll period or on a plan-year basis, and does the plan make a year-end true-up contribution for participants who reach the annual deferral limit before the last pay period?
That single question resolves the entire issue. Get the answer in writing before January, not in December.
When Front-Loading Still Makes Sense
None of this is an argument against front-loading, only against doing it blindly.
Your plan has a true-up. Then front-loading is the better choice, not the worse one. Your money is in the market earlier, the match catches up after year-end, and the only cost is the forgone growth on the delayed match dollars.
You expect to leave mid-year. Deferrals you have already made are yours. If you plan to switch employers in August, banking the deferral early guarantees you use the year’s limit, since a new employer’s plan may have a waiting period.
You are clearing a vesting cliff. If you will satisfy the vesting schedule before you go, getting more employer money credited earlier can matter.
And the reverse trap deserves a mention: back-loading breaks a per-pay-period match too. Someone who contributes nothing until July, then goes heavy, loses the match on every check from January through June, for the same reason. Steady wins under a payroll-period formula, in both directions.
One last limit to keep in view. Your match does not count against the $24,500 elective deferral limit, but it does count toward the Section 415(c) annual additions cap, which is $72,000 for 2026 ($80,000 including catch-up contributions, or up to $83,250 for ages 60 to 63). Most people never approach it. High earners with generous profit-sharing or after-tax contributions do.
If you are 50 or older, your catch-up room is $8,000 ($11,250 for ages 60 to 63), and starting in 2026 that catch-up must be made on a Roth basis if you earned more than $150,000 in the prior year. That changes your paycheck math, since those dollars leave net pay after tax. The details are in 401(k) catch-up contributions for 2026, and the catch-up 401(k) calculator will run the numbers.
Run Your Own Numbers Before January
Three steps, in order:
- Confirm your computation period. Search the SPD, or send the question above to HR.
- Calculate your even rate. Annual limit divided by annual gross pay, then floor it and plan the top-off if payroll needs whole percents.
- Check the paycheck impact before you commit. A jump from 13% to 25% is a real change to your monthly cash flow, and it is easier to see in dollars than percentages.
For that last step, the 401(k) contribution calculator shows how much each deferral rate takes out of every paycheck after the tax savings, so you can compare a 13% deferral against a 25% one on the actual check. The mobile app saves multiple job setups, which makes running two deferral scenarios against each other straightforward. If you want the underlying mechanics of how deferrals move your withholding, how 401(k) contributions affect your paycheck walks through it.
Getting this right takes about fifteen minutes once a year. Getting it wrong costs a four-figure chunk of free money, every year, quietly.
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Frequently Asked Questions
What is a 401(k) true-up?
A true-up is a year-end employer contribution that recalculates your match on full-year pay and full-year deferrals, then deposits whatever the per-paycheck match missed. It is the safety net for anyone who maxed out early or contributed unevenly across the year.
Will I lose my employer match if I max out my 401(k) in October?
Only if your plan matches per pay period and has no true-up. Once your deferrals hit the 2026 limit of $24,500, the deferral stops, and a per-pay-period match stops with it. PSCA's 68th Annual Survey found that among employers matching more often than annually, about a third stop the match with no year-end true-up.
How do I find out whether my plan has a true-up?
Open your Summary Plan Description and search for true-up, computation period, plan year, and payroll period. A match determined on plan-year compensation effectively includes a true-up. A match determined on each payroll period usually does not. ERISA entitles you to the SPD free of charge from your plan administrator.
What contribution percentage lands exactly on the 2026 limit at my last paycheck?
Divide $24,500 by your annual gross pay. At a $180,000 salary that is 13.61%. If payroll only accepts whole percentages, run the floor rate (13%) for most of the year and raise the last one or two checks to top off the difference.
When does a true-up contribution show up in my account?
After December 31, once the plan can see full-year pay and deferrals. Most plans fund it between January and March, though some take until the employer's tax-filing deadline. Your SPD states the funding schedule.
Does my employer's match count toward the $24,500 limit?
No. The $24,500 elective deferral limit applies only to your own contributions. Employer match counts toward the separate Section 415(c) annual additions limit, which is $72,000 for 2026 ($80,000 including catch-up contributions, or up to $83,250 for ages 60 to 63).
I am 50 or older and front-loading in 2026. Does anything change?
Yes. Your deferral limit is $24,500 plus an $8,000 catch-up, or $11,250 if you are 60 to 63. Starting in 2026, the catch-up portion must be Roth if you earned more than $150,000 in the prior year. Those dollars come out of net pay after tax, so the paycheck hit is larger than a pre-tax deferral of the same size.
Can I fix an over-front-loaded year in November?
Partly. Any paycheck that already ran with a zero deferral has a locked-in match loss under a per-pay-period formula. If you still have deferral room left, lowering your rate so that every remaining check contributes at least the percentage your match formula rewards will preserve the match on those checks.