How an employer 401(k) match works

An employer match is money a company adds to an employee's 401(k) because the employee contributed. It is part of total compensation, but unlike salary it is conditional: the amount depends on how much the employee puts in, and keeping it may depend on how long the employee stays. The rules are set by each plan, so two people with the same salary at different companies can receive very different amounts.

How a matching formula works

A match is not required by law. The IRS describes it this way: if the plan document permits, the employer can make matching contributions for an employee who makes elective deferrals. The IRS's own example is a plan in which the employer contributes 50 cents for each dollar the employee defers.

Most formulas have two parts: a rate and a cap. The rate is how much the employer adds per dollar contributed. The cap is the share of pay up to which contributions are matched. Some hypothetical formulas, applied to someone earning $60,000 a year:

The first two rows produce the same employer dollars, but the second requires the employee to contribute twice as much to get them. The last row shows what happens when someone contributes less than the cap: part of the available match goes unused.

Contributing above the cap does not increase the match. In the 50%-of-6% example, someone contributing 10% of pay still receives a match on only the first 6%.

Other kinds of employer contributions

Not every employer contribution is a match. The IRS notes that employers can also make contributions for all participants, including those who do not contribute anything themselves. These are often called nonelective or profit-sharing contributions.

Matches can also be discretionary, meaning the company decides each year whether to make one, or mandatory, as in "safe harbor" 401(k) plans. A safe harbor plan commits the employer to a specified contribution, and that contribution generally must be fully vested when made.

A newer variation comes from the SECURE 2.0 Act. IRS Notice 2024-63 explains that, for plan years beginning after December 31, 2023, employers are allowed to make matching contributions based on an employee's qualified student loan payments. This is optional for employers, and not every plan has adopted it.

Vesting: when the match becomes yours

An employee's own contributions always belong to the employee. Matching money may not, at least at first. Many plans apply a vesting schedule, under which ownership of employer contributions builds over several years of service. Someone who leaves before fully vesting may forfeit the unvested portion.

This matters when comparing job offers or deciding when to leave a job. A generous match with a long vesting schedule may be worth less to a short-tenure employee than a smaller match that vests right away. The post on vesting schedules covers the common schedules and the legal maximums.

Timing: per-paycheck matching and true-ups

Some plans calculate the match each pay period rather than on the full year. That can have an unexpected effect on people who contribute unevenly.

Suppose, hypothetically, an employee earning $120,000 is in a plan that matches 100% of the first 4% of pay, calculated each pay period. If the employee contributes a large share of pay early in the year and reaches the annual deferral limit by midyear, contributions stop for the remaining pay periods. With no employee contribution in those periods, there may be nothing to match.

Some plans correct for this with a "true-up," an extra employer contribution after year-end that brings the match to what the annual formula would have produced. Other plans do not. Whether the plan matches per pay period or annually, and whether it has a true-up, is a question worth asking the plan administrator.

How the match is taxed

Traditionally, matching contributions go into the pre-tax side of the account, even when the employee's own contributions are Roth. The employee owes no tax when the match is made and pays ordinary income tax when the money is eventually withdrawn.

SECURE 2.0 added an option. Under guidance in IRS Notice 2024-2, a plan may let employees designate matching contributions as Roth contributions. In that case the match is included in the employee's gross income for the year it is allocated to the account. Plans are not required to offer this.

How the match fits with annual limits

Employer contributions do not count against the limit on an employee's own deferrals, which is $24,500 for 2026. They do count toward a separate overall cap on total contributions to a participant's account. For 2026, that overall limit is the lesser of 100% of compensation or $72,000, not counting catch-up contributions, according to the IRS contribution limits page.

There is also a ceiling on the pay that can be considered when calculating contributions: $360,000 for 2026, per the same IRS page. For most workers neither figure comes into play. The post on contribution limits explains how the limits fit together.

Where to find a plan's match details

The Summary Plan Description lays out the formula, eligibility rules and vesting schedule. Useful things to look for:

• The match rate and the percentage of pay it applies to
• Whether there is a waiting period before matching begins
• Whether the match is calculated per pay period or annually, and whether there is a true-up
• The vesting schedule for employer contributions
• Whether the match is guaranteed by the plan or decided year by year

For background on the account itself, see how a 401(k) works.