How 401(k) Employer Match Actually Works
A plain-English breakdown of how 401(k) employer matching formulas work, why contributing less than the cap leaves money on the table, and how to calculate your total match.
Employer 401(k) match programs sound simple — "free money" — but the actual formula trips people up more often than expected, because the match is capped by a percent of salary, not by a flat dollar amount most people can eyeball.
The most common match structure
A typical formula reads like "50% match up to 6% of salary," meaning your employer contributes 50 cents for every dollar you put in, but only up to contributions equal to 6% of your pay. Contribute less than 6% and you get a smaller match proportionally; contribute more than 6% and the match stops growing — you just keep funding your own balance past that point.
Worked example
| Your contribution | Match applies to | Employer adds |
|---|---|---|
| 3% of salary | 3% (below cap) | 1.5% of salary |
| 6% of salary | 6% (at cap) | 3% of salary |
| 10% of salary | 6% (capped) | 3% of salary — same as above |
On a $70,000 salary, that's the difference between $1,050 and $2,100 a year in free employer money — purely based on hitting the 6% contribution threshold instead of stopping short of it.
Why under-contributing to the cap is a common costly mistake
Any contribution rate below your plan's match cap means you are leaving part of the match unclaimed — money your employer would have contributed but didn't, because your own contribution didn't reach the threshold it's tied to. Check your plan's specific match formula (it varies by employer) and aim to contribute at least up to the cap before prioritizing other savings goals.
Enter your own match rate and cap into the Retirement / 401(k) Calculator to see exactly how much employer match you're projected to receive over time, and how it compounds alongside your own contributions.