401k Match Calculator
A 401k match is money your employer adds when you contribute, usually a percentage of what you put in up to a cap expressed as a share of salary. Contributing below the cap leaves part of that compensation uncollected, and the uncollected part is what this calculates.
What you capture, and what you leave
Defaults are a $75,000 salary contributing 3% where the employer adds 50% of what you put in, up to 6% of salary.
The min in the formula is the cap doing its work: contributing above it adds your money to the account but no further employer money. Vesting is not modeled here — an unvested match is credited but not yet yours to keep.
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How the number is built
A match has two numbers and they do different jobs. The match rate says how much the employer adds per unit you contribute. The cap says how far up your salary that offer runs.
Match = salary × min(your %, cap %) × match rate
The min is the whole mechanism. Below the cap, every extra point you contribute pulls more
employer money in. Above it, nothing further arrives.
A worked example
Take the defaults: $75,000 salary, contributing 3%, employer adds 50% up to 6% of salary.
You put in 75,000 × 3% = 2,250.
The employer matches 50% of that, so 1,125 arrives.
But the cap allows 6% of salary to be matched, which would have been 4,500 of your money drawing 2,250 of theirs. So 1,125 of employer money is left uncollected.
Raising the contribution from 3% to 6% costs you 2,250 more and brings in 1,125 more from the employer. The account goes from $3,375 a year to 6,750 — it doubles, and so does your own outlay, and $2,250 of that $6,750 is employer money you were never going to be paid otherwise.
Push past 6% and the picture changes shape. Contributing 10% puts in 7,500 of yours against the same 2,250 of theirs. There may be good reasons to do that, but capturing more match is not one of them.
Why the gap is larger than it looks
The 1,125 is one year. Left uncollected for a decade it is 11,250 of employer money, and none of it ever began compounding.
At 7% a year, $1,125 contributed annually for 30 years becomes 106,268 — against $33,750 contributed. That figure is arithmetic on an assumed return, not a forecast, and the return is the uncertain part. The employer’s contribution is not.
Fees run on the same curve in the other direction. On this site’s arithmetic, 5 basis points a year removes 1.5% of a thirty-year pot, 20 removes 5.8%, 75 removes 20.2% and 150 removes 36.5% — so a plan with expensive default funds gives some of the match back.
Vesting
A match can be credited to the account without being yours yet. Cliff vesting hands you the whole balance at a date; graded vesting releases it in steps. Leave before the schedule completes and the unvested portion goes back.
Your own contributions are always yours. Vesting applies only to the employer’s part, and it is the one input this calculator deliberately does not model, because the schedule is written into your specific plan document rather than being a general rule.
Read the schedule before treating a match as compensation you can count on. If you are eighteen months from a cliff, that is a real number in a decision about changing jobs.
The two shapes a match comes in
Most plans use one of two formulas and they are not equivalent. A dollar-for-dollar match sets the match rate to 100%: contribute 4% of salary and 4% arrives. A partial match sets it lower — 50% is the common one — so reaching the same employer contribution takes twice the contribution from you.
Set the match rate input to whichever your plan uses. The formula is in your benefits portal, or ask HR for the plan’s Summary Plan Description, which states the match rate, the cap and the vesting schedule. On the defaults, moving it from 50% to 100% turns the 1,125 left behind into 2,250, on identical contributions.
Ask about a true-up as well. Plans that match per pay period sometimes reconcile at year end and pay any shortfall; plans without that provision do not, and front-loading contributions into the first half of the year permanently forfeits the later matches.
The original data
Of the 24,971 unique videos in the finance search study this site keeps, 22 have 401k or 401(k) in the title, at a median of 81,626 views across 20 channels — 36% of them instruction-shaped and 5% calculator-shaped. Retirement targets appear in 17 at 87,636 and Roth accounts in 24 at 95,293.
22 videos at a 81,626 median, against 195 position-sizing videos at 1,738. Retirement subjects carry far more search demand than trading subjects and almost none of the coverage hands anyone the arithmetic.
The question: Money is tight. Skip this year and catch up later?
The answer is that the match cannot be caught up. Contribution limits are annual and the match is calculated on what you put in during that year, so a year skipped is an offer that expires rather than one that carries forward. Catching up later replaces your own money and never replaces theirs — which is the specific reason this ranks above almost everything else you could do with the same money.
The order this site uses everywhere: first a small starter cash buffer for surprises, then enough 401k contribution to collect the full match, then pay off high-interest debt, then finish the emergency fund, then more retirement saving.
The limit the cap sits inside is far higher. For 2026 the IRS caps your own 401k contributions at $24,500 (plus an $8,000 catch-up from age 50, or $11,250 at ages 60 to 63), and the employer’s match does not count against that figure. Check the current year’s limit, because it changes most years.
When it fails
The most common misreading is treating the cap as a share of the contribution rather than of salary. “50% up to 6%” does not mean the employer stops at 6% of what you put in; it means the first 6% of your salary is eligible. Getting that backwards produces a contribution rate far below what captures the full offer, and the mistake is invisible because the account still grows.
The second failure is per-pay-period matching. Some plans match each check rather than the year, so front-loading contributions can miss later matches entirely.
A third is ignoring vesting. An unvested match is credited, not kept.
A fourth is assuming the plan’s default rate captures the cap. Auto-enrolment often starts at 3%.
A fifth is treating the assumed return as certain. The match is contractual; the growth is not.
And a sixth is contributing far above the cap for match reasons. Past it, no further employer money arrives, and the decision becomes a different one about tax and access.
Related
401k covers the account, its limits and its withdrawal rules. Compound interest is why an uncollected year costs more than its face value. And index funds is usually what the balance is actually invested in.
This is the one piece of arithmetic on the site where the answer is unambiguous. Almost everything else here involves a judgment about risk or a forecast that might be wrong. Once a small starter cash buffer is in place, contributing enough to reach the cap is just collecting compensation you have already been offered, and the only reason not to is that the money genuinely is not there this month.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.