401(k) Max-Out Per Paycheck Calculator

How to work out your 401(k) max-out amount per paycheck

The method is subtract, then divide. Take your annual elective deferral limit, subtract what you have already deferred since January 1, and divide the remainder by the paychecks you have left. That is it. Everything else on this page is about the two traps sitting either side of that arithmetic.

The first trap is the paycheck itself. Your gross check is your annual salary divided by the number of paydays in a full year, not by the number of paydays left. A $90,000 salary paid biweekly is a $3,461.54 gross check in August and a $3,461.54 gross check in January. How many checks remain changes how fast you have to fill the room, never what a check is worth.

The second is that the answer is two numbers, not one. The IRS caps a dollar amount, but payroll systems almost always take a percentage of pay. Starting from zero on 26 biweekly checks, the 2026 base limit of $24,500 works out to $942.31 a check, which on that salary is a 27.3% deferral. Other frequencies, at the base limit for a full year:

• Weekly (52 checks): $471.16 a check
• Biweekly (26 checks): $942.31 a check
• Semi-monthly (24 checks): $1,020.84 a check
• Monthly (12 checks): $2,041.67 a check

Round the percentage up rather than to the nearest whole number. Overshooting is harmless, because the plan stops your deferral the moment you reach the limit. Undershooting is not: you finish December under the limit with no way to go back and add the difference. If your payroll system only accepts whole percentages, the calculator shows the whole-percent version and what the overshoot comes to in dollars, which is usually small enough to ignore.

2026 401(k) limits and the three catch-up tiers

Your limit depends on the age you reach by December 31 of the plan year, and there are three bands rather than the two most calculators offer:

The enhanced catch-up introduced by SECURE 2.0 is a four-year window, not a permanent upgrade. Turn 64 and you go back to the standard amount, which is exactly why the age control on this page is a three-way choice instead of a checkbox.

Employer money sits outside all of this. The match counts against the separate Section 415(c) annual additions limit, $72,000 for 2026, so a generous match never shrinks your own room. One tax-treatment change does arrive in 2026: if your prior-year FICA wages with the same employer were more than $150,000, your catch-up contributions have to go in as Roth. The dollar limits do not move, so the numbers above are unchanged, but Roth dollars give no upfront deduction and your take-home drops by the full amount.

Front-loading, the per-period match, and the true-up question

Front-loading means deferring at a high rate early so you hit the limit well before December. Whether it costs you money comes down to one question about your plan: does it true up the match at year end?

Most plans compute the match each pay period, on that period's deferral. If you hit the limit in July, your deferral stops, and in a per-period plan the match stops with it. Say the formula is 50% of the first 6% on a $3,461.54 biweekly check. The full match is $103.85 a check. Reach the limit with 11 checks to go and you leave about $1,142 of employer money on the table, permanently. A plan with an annual true-up backfills that shortfall after year end, in which case front-loading costs nothing and actually helps, because the money is invested sooner.

The calculator assumes no true-up, which is the conservative reading. Check the summary plan description, or ask HR: does the plan true up the match at year end? It is a yes-or-no question and it changes the right strategy completely.

The safe middle ground is the match-safe rate: spread the remaining room evenly so that every paycheck still carries a deferral, and keep that rate at or above the percentage your match stops at. When the room left is too small for both, the calculator shows the two paths side by side instead of picking one for you. If you want the employer-side view of what that match costs the business, the employer payroll cost calculator breaks it out.

Reading your 401(k) deferral and match on a pay stub

Every input on this page except the plan formula is printed somewhere on your stub. The deferral is a pre-tax deduction line with a year-to-date column beside it, and that year-to-date figure is the number to type into "already deferred". The employer match is an employer contribution line: it appears on the stub but does not reduce net pay, because it is not your money coming out of your check. If those two lines are hard to tell apart, what YTD means on a pay stub walks through the column layout, and gross to net pay covers the order deductions come out in.

One caveat on the take-home estimate: a traditional deferral is exempt from federal income tax withholding but not from Social Security or Medicare, so your FICA lines do not shrink when you raise your deferral. The pre-tax vs post-tax deduction calculator models that properly if you want the full picture rather than a single-rate estimate.

Payslip44 builds the stub these figures live on: per-line pre-tax deduction and employer contribution items, year-to-date amounts on every line, reusable employer and employee templates, and decimal-precise money math that will not drift by a cent across 26 paychecks. It all runs on-device, and finished stubs export to PDF, PNG, CSV, or plain text. Once you have set your deferral, download Payslip44 and check the numbers against a real stub.