401(k) calculator with employer match
An employer match is money added to your account for contributing your own, up to a plan-set limit - and it’s easy to under-contribute without realizing part of it goes unclaimed. This calculator projects your 401(k) balance from your contribution rate and the match formula, and flags any match you’re leaving on the table.
How the math works
Your yearly contribution is your salary times your contribution percentage. The match only applies up to the plan’s cap - contributing beyond the cap percentage adds to your own balance but stops adding to the match. Each year, your contribution plus the match is added to the balance and the whole thing grows at the assumed rate. If your contribution rate sits below the match cap, the calculator shows exactly how much matched money you’re not collecting per year and over your full timeline - that gap is money the plan would otherwise add on top of what you put in, and it’s the first thing worth closing before increasing contributions further.
Related reading
Start with how an employer 401(k) match works if the mechanics are new, and how catch-up contributions interact with the match if you’re 50 or older. Whether it’s worth stretching contributions to capture the full match walks through the trade-offs, and whether employer match counts toward the annual contribution limit clarifies a common point of confusion. Also see how 401(k) vesting works - match money isn’t always yours immediately.
The formula this calculator uses
your contribution = salary * your percentage
matched percentage = min(your percentage, employer cap)
employer match = salary * matched percentage * match rate
match left behind = salary * (cap - your percentage) * match rate, if positive
What it assumes without asking
- The match formula is a flat rate up to a cap, which is common but not universal
- Salary does not change over the projection
- The match is counted when it lands, before any vesting schedule
One example, computed in full: $80,000 salary, 50% match on the first 6%
| You contribute | Your money | Employer match | Total in | Match left behind |
|---|---|---|---|---|
| 0% | $0 | $0 | $0 | $2,400 |
| 2% | $1,600 | $800 | $2,400 | $1,600 |
| 3% | $2,400 | $1,200 | $3,600 | $1,200 |
| 4% | $3,200 | $1,600 | $4,800 | $800 |
| 6% | $4,800 | $2,400 | $7,200 | $0 |
| 8% | $6,400 | $2,400 | $8,800 | $0 |
| 10% | $8,000 | $2,400 | $10,400 | $0 |
What this calculator does not model
- Vesting. An unvested match is not yet your money, and leaving early can forfeit it
- The annual contribution limit set by the IRS, which caps the top rows
- Whether the plan’s investment options and fees are any good, which matters more over 30 years than the match does
The guide behind this tool
A number on its own does not tell you what to do with it. The last column is the whole point of the tool. Investing a small amount while paying off debt sets an employer match against interest avoided, at every debt rate.
Sources & further reading
This tool is a general educational estimate, not financial advice or a projection of actual plan performance. Match formulas, vesting rules, and contribution limits vary by employer and by year. See our disclaimer.