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401(k) Calculator with the Match Timing Trap Shown

An estimate, not financial or tax advice. Plan rules differ on matching, vesting, true-up and the super catch-up, and only your plan document settles them. Limits are the 2026 IRS figures and change annually.

Maxing out early can cost you thousands of match a year. If your employer matches per paycheck and the plan has no true-up, hitting the annual limit in month four stops the match for the remaining eight. On $150,000 that is $2,942 a year — $277,933 over a career. No other 401(k) calculator mentions it.

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2026 IRS limits. Before tax, and excluding any Social Security. Runs entirely in your browser.

The front-loading trap

Spreading contributions across all 26 paychecks collects the full 4,500 dollar match, while contributing 50 percent per cheque reaches the annual limit at paycheck 9 and collects only 1,558 dollars, losing 2,942 in a single year SAME $24,500 CONTRIBUTED — TWO DIFFERENT MATCHES Spread across all 26 paychecks Match collected: $4,500 50% of each paycheck — limit reached at paycheck 9 no contribution, no match Match collected: $1,558 — $2,942 lost $150,000 salary, 50% match to 6%, no true-up. The same $24,500 goes in either way; only the timing differs. Compounded at 7% over thirty years, that annual gap is $277,933 — from a scheduling choice, not a saving one.
A true-up provision fixes this by reconciling the match at year end, and many plans have one. Many do not, and the plan document is the only place that says which. It is worth ten minutes to find out.
Contribution patternMatch collectedNote
Even across 26 paychecks$4,500The full match. 6% of salary matched at 50%
50% per paycheck$1,558Limit hit at paycheck 9. Nothing contributed after, so nothing matched
Either, with true-up$4,500The plan reconciles at year end and pays what you would have received

The money contributed is identical. Only the schedule differs. This is the rare financial mistake that costs a large amount for no benefit at all — the front-loader does not even gain meaningful extra growth, because the money is in the market only a few months earlier.

2026 contribution limits

Your ageStandardCatch-upTotal you can defer
Under 50$24,500$24,500
50–59$24,500$8,000$32,500
60–63$24,500$11,250$35,750
64 and over$24,500$8,000$32,500
The super catch-up replaces the standard catch-up. It does not stack with it. At 60 to 63 the figure is $11,250 instead of $8,000, not $19,250 — and several finance sites get this wrong. It also applies only in the calendar years you are 60, 61, 62 or 63; at 64 it drops back to $8,000. Your plan may choose not to offer it at all.

A second SECURE 2.0 change bites from 2026: if you earned more than $145,000 in FICA wages from that employer in the previous year, any catch-up contribution must be made as Roth — after tax. If your plan has no Roth option, you cannot make catch-up contributions at all. The threshold is per employer, so wages from a previous job do not count towards it.

The match is the return, before the market does anything

Match formulaOn $90,000Immediate return on your money
100% up to 3%$2,700100% on the first 3% you contribute
50% up to 6%$2,70050% on the first 6%
100% of first 3%, 50% of next 2%$3,600Tiered. Common and easy to under-contribute against
25% up to 8%$1,80025%, but requires a larger contribution to capture

A 50% match is a 50% return in the instant it is paid, before the market has done anything at all. No investment reliably offers that, which is why contributing less than the matched amount is the one decision in personal finance with no defensible case.

Vesting, and the money that is not yours yet

ScheduleHow it worksIf you leave early
ImmediateYours from day oneYou keep everything
CliffNothing, then all of it at once — typically 3 yearsLeaving at 2 years 11 months forfeits all employer money
GradedUsually 20% a year over 5 or 6 yearsYou keep the vested share and forfeit the rest

Your own contributions are always immediately yours. Vesting applies only to the employer’s money. If you are considering a move and are close to a cliff date, the arithmetic on waiting a few weeks is occasionally startling — and it is the only case where a resignation date is worth calculating.

Common mistakes

Front-loading without checking for true-up. Hitting the limit early stops the match for the rest of the year unless the plan reconciles at year end. On $150,000 with a 50% match to 6%, that is $2,942 lost annually and $277,933 over thirty years — for identical contributions.
Contributing below the match cap. Every percentage point below it is matched money declined. If the plan matches 50% to 6% and you contribute 4%, you are leaving 1% of salary on the table each year — and it compounds for as long as you would have held it.
Cashing out when changing job. An early withdrawal is taxed as income and usually carries a 10% penalty, so a $50,000 balance can arrive as $32,000 — and the compounding it would have done is gone permanently. A rollover to the new plan or an IRA costs nothing.
Ignoring the fund fees inside the plan. 401(k) menus vary enormously, from index funds at a few basis points to actively managed options above 1%. The difference over a career is measured in six figures, and switching fund is usually a two-minute change on the provider’s site.

Frequently asked questions

Can maxing out early cost me money?

Yes, if your employer matches per paycheck and the plan has no true-up. Reaching the annual limit in month four means no contribution in months five to twelve, and therefore no match. On $150,000 with a 50% match to 6%, that is $2,942 a year for exactly the same contribution.

What is a true-up?

A provision that reconciles the match at year end, paying whatever you would have received had contributions been spread evenly. Many plans have one and many do not. The plan document or your benefits team will say, and it is the single most valuable thing to check before changing your contribution rate.

How much can I contribute in 2026?

$24,500 as an employee deferral. From 50 you can add an $8,000 catch-up for $32,500. At 60 to 63 the catch-up is $11,250 instead, for $35,750 — it replaces the standard catch-up rather than stacking, and reverts to $8,000 at 64.

Does the employer match count towards my limit?

No. The $24,500 applies to your own deferrals. Employer contributions count towards a separate, much higher combined limit, so a generous match never reduces what you can put in yourself.

Why must high earners make catch-ups as Roth?

A SECURE 2.0 provision effective from 2026. If your FICA wages from that employer exceeded $145,000 in the prior year, catch-up contributions must be after-tax Roth. The threshold is per employer, and a first year with a new employer is generally exempt because there is no prior-year wage history.

Is the employer match taxed?

Not when it is paid. Traditional matching contributions go in pre-tax and are taxed as income on withdrawal, like the rest of a traditional balance. Some plans now offer a Roth match, which is taxed in the year it is paid and comes out tax-free instead.

What happens to my 401(k) if I change job?

Your own contributions are always yours. The employer’s portion depends on the vesting schedule — a three-year cliff forfeits all of it if you leave at two years and eleven months. You can usually leave the balance, roll it to the new plan, or roll it to an IRA. Cashing out is the expensive option.

Traditional or Roth 401(k)?

Traditional deducts tax now and charges it on withdrawal; Roth does the reverse. The deciding question is whether your tax rate in retirement will be higher or lower than today, which nobody knows — which is why splitting between the two is a common hedge rather than an admission of indecision.

Is anything I enter sent anywhere?

No. Everything runs in your browser with no server request, and works offline once the page has loaded. Nothing is written to disk and nothing persists after you close the tab.

Sources

  • Internal Revenue Service. “401(k) limit increases to $24,500 for 2026.” The 2026 deferral, catch-up and phase-out figures used throughout this page.
  • IRS Notice 2025-67 (13 November 2025). Cost-of-living adjustments for 2026 retirement plan limits, including the super catch-up remaining at $11,250.
  • IRS, Retirement topics — catch-up contributions. Confirms the age 60–63 limit applies instead of, not in addition to, the standard catch-up.
  • SECURE 2.0 Act of 2022, section 109, and IRC §414(v)(2)(E)(i). The statutory basis for the super catch-up and for the Roth catch-up requirement for high earners.
  • US Department of Labor, Employee Benefits Security Administration. Vesting schedule rules and the disclosure requirements that make a plan document the authority on matching and true-up.
  • Formula. Match per pay period is min(your deferral, salary × match cap ÷ periods) × match rate, summed across periods. Front-loading loses match because deferrals stop once the annual limit is reached, and a per-period match cannot be earned on a zero contribution.

Every figure in the tables above is computed from these formulas rather than quoted, so the article and the calculator cannot disagree. Plan rules override all of it — matching formula, vesting, true-up and whether the super catch-up is offered are each the employer’s choice within the limits above.

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