What a 401(k) True-Up Contribution Actually Is

A 401(k) match is advertised as a percent of your pay. The way the dollars actually arrive is often a percent of each paycheck, and only of the paychecks where you deferred. If you hit the annual deferral limit in August, the paychecks after August may carry a deferral of zero, and a per-paycheck match of zero, even though you "did everything right" and maxed the plan. A true-up is the employer's later deposit that fills the gap between the match you received and the match the annual formula would have produced. Some plans do it. Some never will. The summary plan description tells you which kind you have. The payroll portal usually does not.

The limit and the match are different caps

For 2026 the IRS raised the employee elective deferral limit to $24,500 for 401(k), 403(b), most governmental 457 plans, and the Thrift Savings Plan. If you are age 50 or older, the general catch-up limit is $8,000, so the combined employee ceiling many people quote is $32,500. If you are age 60, 61, 62, or 63, a higher catch-up applies instead of the $8,000. For 2026 that higher catch-up remains $11,250. Added to $24,500, that is $35,750 of employee deferrals. Catch-up dollars are not the same thing as the match. A match formula is usually a percent of pay, up to a percent of pay. Putting in more of your own money past the match threshold does not, by itself, make the employer write a bigger check.

The IRS also caps how much of your pay the plan is allowed to count. For 2026 that compensation limit is $360,000. And the overall annual addition limit, employee plus employer plus forfeitures, before catch-up, is $72,000. A household making $78,000 will not bump into either of those ceilings. A household making $400,000 might. True-up math still starts with the match formula in the plan document, not with the IRS maximum. The IRS maximum is the fence. The formula is the path inside the fence.

None of those figures is a recommendation to defer $24,500. They are the 2026 published limits so the example below can use a real cap instead of a round number from an old article. If paying the rent depends on a fatter paycheck, a smaller deferral that still captures the match is the comparison that matters. The true-up question only shows up once your deferral pattern, not just your annual total, interacts with the formula.

A $78,000 salary, biweekly, with the arithmetic visible

Labeled example. Salary $78,000. Paid every two weeks, 26 pays. Each paycheck's gross is $3,000, because 78,000 divided by 26 is 3,000. The plan matches 100 percent of the first 4 percent of pay. If the formula is applied to the whole year, 4 percent of $78,000 is $3,120. That is the match a person would expect from the brochure.

If the formula is applied to each paycheck, the match on a paycheck is 4 percent of that paycheck's $3,000, which is $120, and only if you deferred at least 4 percent of that paycheck. Defer less than 4 percent on a given check and that check's match shrinks. Defer nothing and that check's match is zero. Defer more than 4 percent and that check's match stays $120. Extra deferral above 4 percent does not buy extra match on that check.

Now front-load. You defer $1,500 per paycheck, half of gross. Fifteen paychecks times $1,500 is $22,500. The sixteenth paycheck needs only $2,000 more to reach the 2026 deferral limit of $24,500, because 22,500 plus 2,000 is 24,500. You are allowed to defer $2,000 of a $3,000 check. Paychecks 17 through 26 then have a deferral of zero if you have no catch-up room. You are under 50 in this example, so you do not.

Every one of those first 16 paychecks deferred far more than 4 percent, so each earned the $120 match. Sixteen times $120 is $1,920. The annual brochure number was $3,120. The gap is $1,200. Without a true-up, that $1,200 never arrives. You maxed the employee limit and you still missed more than a third of the match, because 1,200 divided by 3,120 is about 38 percent. The miss is not a penalty. It is the formula, applied to the paychecks that actually contained a deferral.

What changes if you spread the same $24,500

Spread across 26 paychecks, $24,500 is about $942.31 each. A clean way to hit the limit without a rounding mess is 25 paychecks at $942 and a last paycheck at $950. Twenty-five times 942 is 23,550. Plus 950 is 24,500. Each of those deferrals is well above 4 percent of $3,000, since 4 percent is $120 and $942 is far larger. Every paycheck earns the $120 match. Twenty-six times $120 is $3,120. The gap is zero. You did not defer more dollars than the front-loader. You deferred the same $24,500 on a calendar the formula could see.

The tradeoff is cash flow. The front-loader's early paychecks are much smaller, and the later paychecks are larger because deferrals have stopped. The spreader's paychecks are steady and smaller all year. One of those shapes fits a household that wants the tax break early. The other fits a household that wants the match without depending on a true-up. If you do not know whether the plan true-ups, the spreader's shape is the one that does not need the answer.

Catch-up changes the calendar and not the idea. An extra $8,000 at age 50, or $11,250 at ages 60 through 63, means you hit $24,500 and you are still allowed to defer. If those later deferrals are at least 4 percent of pay, a per-paycheck match can continue. If you stop deferring because you thought "the limit" meant $24,500 and you forgot you had catch-up room, the match on the later checks can still go to zero. Read the limit that applies to your age before you set the payroll percent to zero in October.

What a true-up actually deposits

A true-up looks back at the year. The plan administrator applies the match formula to annual compensation and annual deferrals, subtracts the match already posted with each payroll, and deposits the difference. In the example the difference is $1,200. The deposit might land in January or February of the next year, or later if the plan's correction calendar is slow. It is still employer money for the year being trued up, subject to the plan's vesting schedule. A true-up does not vest faster than any other match. If you are 40 percent vested, you are 40 percent vested in the true-up too.

Many true-up provisions include a last-day rule or an hours rule. If you quit in November, the plan may owe you nothing for the true-up even though the per-paycheck gap is real. The front-loaded employee who leaves before the true-up date can lose the $1,200 and also have locked away a large deferral early in the year. That is a reason to read the rule before you front-load in a year you might change jobs. It is not a reason to skip the match you can capture on the way out the door.

Some plans do not need a true-up because the formula is already annual, or because they match each paycheck and also calculate a year-end adjustment under a different name. "True-up" is the word participants use. The document might say "annual match true-up," "year-end reconciliation," or nothing at all. If the document is silent, assume you do not have one. Ask human resources for the paragraph, not for a vibe. A verbal "we usually make people whole" is not a plan term.

Where people misread the pay stub

The stub shows a match of $120 and a deferral of $1,500 and both numbers look healthy. Nothing on the stub says "you will get zero match in November." You have to project the limit. Divide the remaining room under $24,500, or under your catch-up ceiling, by the deferral per check. That quotient is how many checks of match you have left. In the front-load example the quotient ran out at check 16 of 26. The stub was not wrong. It was local.

A mid-year raise changes the 4 percent. A bonus that is eligible compensation can be a match opportunity or a match miss, depending on whether you defer from the bonus and whether the plan counts the bonus. A bonus that is excluded compensation cannot be matched no matter what you elect. The document's definition of compensation is the dull page that decides this. Print it.

Two jobs in one year share one employee deferral limit across 401(k) and 403(b) plans. You can max out at job one in June and have no legal room at job two, except catch-up if you qualify and except a separate 457(b) limit if you have one. A true-up at job one does not create new deferral room at job two. If job two has a generous match and you already used the limit, you cannot defer to capture it. Leaving a little room when you know a job change is coming is a planning choice. It is not always available in hindsight.

A year you can check in one sitting

Pull the summary plan description and find the match formula and any true-up or last-day sentence. Write the 2026 ceiling that fits your age: $24,500, or $32,500, or $35,750. Divide your salary by the number of pays. Multiply one paycheck by the match percent and confirm it equals the match on the stub. Then run the front-load path and the spread path on a piece of paper. If the front-load path leaves a gap and the document has no true-up, change the election so every remaining paycheck defers at least the match percent, until the annual ceiling arrives as late in the year as you want.

If a higher deferral will make the checking account thin, do not fund the gap with a credit card. The match is valuable and a revolving balance at a card APR is a faster leak. Keep a small cash buffer in a high-yield savings account so a car repair does not force you to cut the deferral to zero and lose the rest of the year's match. The buffer is not the investment. It is what lets the deferral stay on.

After year-end, if the plan does true-up, look for the deposit. If the gap was $1,200 and the deposit is $1,200, you are done. If it is missing and the document promised it, ask the administrator with the payroll dates in the email. Plans miss true-ups. A polite written question with your own arithmetic is how those misses get fixed. You are not accusing anyone. You are reconciling a formula.

A percent-of-pay election that does the spreading for you

You do not have to deposit a flat dollar amount. Most payroll systems take a percent. On the $3,000 biweekly check, 4 percent is $120, which captures the full match on that check and defers only $3,120 for the year, the same number as the match itself. That is the minimum path. It never hits the $24,500 employee ceiling, and it never creates a true-up gap, because every check has a deferral of exactly the match threshold. If you want to defer more, raise the percent, then watch the year-to-date deferral against your ceiling.

Suppose you elect 20 percent. Twenty percent of $3,000 is $600. The 2026 ceiling of $24,500 divided by $600 is 40.83 checks, and you only have 26. So 20 percent never reaches the ceiling in this salary. Twenty-six times $600 is $15,600. Every check still clears the 4 percent match test. The match is the full $3,120, and you deferred $15,600 rather than $24,500. There is no true-up drama because you never zeroed out a paycheck. The drama starts when the percent is high enough to exhaust the ceiling before the last check.

Find that danger percent. $24,500 divided by 26 checks is about $942 a check, and $942 divided by $3,000 is about 31.4 percent. An election above roughly 31 percent of pay, on this salary and this pay calendar, will hit the 2026 ceiling early if you are not eligible for catch-up. An election at or under that percent, held steady, keeps a deferral on every check. Write your own version: your ceiling, divided by your number of pays, divided by your gross paycheck. That quotient is the highest steady percent that still does not need a true-up. If you elect more than that, you are choosing the front-load path, and you need the document's true-up sentence to be real.

Mid-year changes reset the projection. If you ran 10 percent for half the year and then jump to 40 percent, you can still exhaust the ceiling in the fall. Recompute when you change the percent, when you get a raise, and when a bonus check is about to defer at the same percent as regular pay. A bonus of $6,000 at 40 percent defers $2,400 in one day and pulls the ceiling forward. The match on the bonus depends on whether the plan counts it. The ceiling does not care. Employee deferrals from the bonus still consume the $24,500.

What not to do with the $1,200 story

Do not skip the match while you wait to understand true-up. A per-paycheck match you can capture this Friday is worth more than a perfect spreadsheet in March. Do not assume every employer true-ups because a former employer did. Do not treat catch-up as automatic. The plan has to allow it, and your age has to fit the year's rule. Do not confuse the employee ceiling with the employer match. Maxing one is not the same as receiving the other.

One more calendar trap belongs on the same page. A plan year is not always the calendar year. Your employee deferral limit is a calendar-year limit. The match formula might run on a plan year that ends in June. A true-up, if it exists, follows the plan year in the document, which may not be the day you personally hit $24,500. When you ask human resources which year the true-up covers, ask which twelve months, not just "do we have one." Getting a January deposit that true-ups last July through this June is a success. Waiting for a January deposit that was never tied to the calendar year you just finished is how people think the employer welched. The dates are in the document. Put them next to the $1,200 arithmetic before you decide the election percent for the rest of the year.

The useful habit is small. Know whether your match is per paycheck or per year. If it is per paycheck, keep a deferral of at least the match percent on every check until you are done for the year, unless a written true-up will honestly fill the hole. In the $78,000 example, that habit is the difference between $1,920 and $3,120. Same employee dollars. Different employer dollars. The document decides which one you get.