Tool · Money
Type in your pay and your plan's matching formula, and the calculator shows the money your employer would add each year, what putting in enough to get it costs you in take-home pay, and what the match would grow to by the time you retire.
Where does each number come from?
- Your salary
- Gross pay for the year, before anything comes out — the top line on your pay stub times the number of pay periods. The calculator holds it flat; raises are outside the model.
- Your employer matches … on the first …
- Your plan’s formula, in two numbers: how many cents your employer adds for each dollar you put in, and the share of your pay that applies to. Both are in your plan’s summary plan description — a document HR or your plan’s website has, and the one thing worth finding before you type. The box starts at fifty cents on the first six percent, which is a made-up plan to show the shape, because there’s no published typical match to borrow.
- Years to retirement, and yearly growth
- How long the matched money compounds, and the rate it grows at. The table shows a no-growth column beside it, which is just the match added up.
- Your tax rate
- Used for one line only: what the contribution costs you in take-home pay. Because it goes in before tax, your paycheck drops by less than the amount you put in.
What moves the answer?
Let’s say you make $60,000 and your plan matches fifty cents on the dollar for the first six percent of pay. Putting in six percent is $3,600 a year, and your employer adds $1,800. At a 22% tax rate that $3,600 costs you about $2,800 in take-home pay, so you’re putting $1,800 of somebody else’s money into your account for about $2,800 of your own.
Skip it for thirty years and the match alone is $54,000 you never collected. Let that $1,800 a year grow at 5% for the same thirty years and it’s about $120,000. The match formula and the years are what move that figure; the tax rate only moves the take-home line.
What does the calculator take as given?
- The 2026 plan limits
- You can put $24,500 of your own pay into a 401(k); you and your employer together can put in $72,000; and a plan can only match on the first $360,000 of pay. All three come from IRS Notice 2025-67 of 13 November 2025, and the calculator warns when one of them bites.
- The tax rate
- Starts at 22%, one of the 2026 brackets from the IRS’s Revenue Procedure 2025-32.
- The growth rate
- Starts at 5.01%, the ten-year Treasury yield on 18 September 2026 from the Federal Reserve’s daily release — a government bond rate, not a forecast. Every figure here is in The Money Numbers with its quote and date.
- What's left out
- The catch-up limits for people 50 and over, because the calculator doesn’t ask your age; they raise your own ceiling and leave the match alone. And vesting — a match you leave the company before it vests isn’t yours. Your plan’s vesting schedule, its fees and any true-up rule are in the same summary plan description as the formula.
The sixty-thousand salary and the fifty-cents-on-six-percent plan are stand-ins for yours; the formula that decides your real number is printed in your summary plan description, and your pay stub has the other half.
Sources
- Internal Revenue Service, Notice 2025-67 — 2026 employee deferral limit $24,500; section 415(c) total $72,000; compensation limit $360,000 (released 13 November 2025).
- Internal Revenue Service, Revenue Procedure 2025-32 — the 22% bracket for tax year 2026.
- Federal Reserve, Statistical Release H.15 — 10-year Treasury constant maturity, 5.01% on 18 September 2026, release of 21 September 2026.
- Bills & Beans, The Money Numbers That Change Every January.