401(k) Calculator: Retirement Balance With Employer Match

Disclaimer: This calculator is provided for educational and estimation purposes only and does not constitute formal financial advice.

What this calculator actually answers

A FIRE calculator asks the uncomfortable question: how big does your portfolio need to be? This one asks the more practical question that comes first for most people: what will my account actually have in it when I retire — given what I contribute, what my employer matches, and how long both have to compound?

The difference matters. The FIRE answer is a target that has nothing to do with your current 401(k) — it is annual expenses times a withdrawal-rate multiplier, and the FIRE calculator is the right tool for it. This calculator is the projection side of the same plan: take the money actually going into the account, run it forward at a growth rate, and report the number at retirement in two currencies — the nominal sticker price, and what that price is worth in the dollars you spend today.

The match formula: “50% up to 6%”

Most employers quote their match as two percentages: the share of your contribution they will match, and the share of your salary that match applies to. The default — 50% up to 6% — is the classic shape. The match money is the smaller of the two caps:

$$Match = MatchPct \times \min(Contribution,\ Salary \times CapPct)$$

On an $80,000 salary that resolves to a simple ladder. The table below is the model’s own output at each contribution rate:

Two things stand out. First, the match maxes out at 3% of salary — $2,400 — and it does so at exactly the cap: the employer’s half of 6%. Second, going from 4% to 6% adds $1,600 to your contribution and $800 to the match — matched money is the highest-returning “investment” available to most households, because the employer is literally doubling part of the deposit. Going from 6% to 8% adds $1,600 of your money and nothing from the employer. The cap is the break point: contribute at least to it, and decide anything beyond it on its own merits.

The projection: where the money ends up

The account grows monthly, compounding the nominal return while a deposit lands at the end of each month. With monthly rate $i = r/12$ over $n$ months:

$$FV = P(1+i)^n + M \times \frac{(1+i)^n - 1}{i}$$

where P is the starting balance, M the monthly deposit (your contribution plus the match, divided by twelve), and r the nominal annual return.

Run the defaults: a 30-year-old with $80,000 of salary, an 8% contribution, and a 50%-up-to-6% match puts $6,400 of their own money and $2,400 of employer money into the account each year — $8,800 total, or $733 a month. With $25,000 already saved, 35 years at 7% reaches $1,608,427.

That number has three sources, and the split is the part of the projection people get wrong:

Four out of every five dollars at retirement are growth — money nobody deposited. That is not an accident of the inputs; it is what compounding does to a 35-year horizon, and it is why the chart’s curve bends so sharply upward in the final years. After five years the balance is $87,942; at thirty-five it is $1,608,427. The last decade alone does most of the work.

The return does more than the contribution

Holding every other input at the defaults, the assumed return moves the projection more than any other dial on this page:

A two-percentage-point change in the return assumption swings the projection by roughly $600,000–$1,100,000 — several times the entire employer match over the same horizon. That is the honest context for the 7% default: it sits in the middle of the historical range for a diversified equity-heavy portfolio before fees, and small fee differences matter because they compound for decades. Run the same inputs through the compound interest calculator with the rate set to 7% and the monthly deposit to $733 to see the identical math from the other side.

Inflation: the number the sticker price hides

The nominal balance is the figure in the account statement at retirement — and it is the wrong number to compare against your spending today. At 3% inflation, the $1,608,427 projection has the purchasing power of $571,608 in today’s dollars, barely a third of the sticker price:

The nominal balance is identical across all three rows — inflation does not change what the account statement says; it changes what that statement buys. That is why the chart draws two lines: the nominal projection and the same balance deflated month by month, so the gap between them is the tax inflation levies on a long horizon. Planning against the nominal number alone is how retirees discover their “million dollars” is $571,608 of today’s purchasing power. The inflation-adjusted savings goal calculator solves the mirror-image problem — how much a future target costs in today’s money — and is the right tool for checking whether a specific goal (a house, a car, a college bill) keeps its value.

Where the assumptions break

A good projection is honest about what it does not model:

• Fees. A 1% annual fee on a 7% gross return silently becomes a 6% return for the entire projection — and at 6%, the same inputs produce a materially smaller balance. The return input should be net of fees, not the fund’s headline number.
• A static contribution. Real contributions rise with raises and cost-of-living bumps. This model holds the percentage fixed, which understates the balance for most working careers.
• A static match. Employers change match formulas; this model holds the one you entered constant for 35 years.
• IRS limits and vesting. The contribution input is a percentage of salary with no cap; the IRS limits 2026 employee elective deferrals to $24,500 a year ($32,500 from age 50, $35,750 for ages 60–63), so a large percentage on a high salary can produce a number the law does not actually allow. Employer match dollars can also vest gradually — leaving a job before that schedule completes forfeits the unvested share this model still counts as saved.
• A static rate. The projection uses one return for the whole horizon; real portfolios swing year to year, and the sequence of those swings matters for the ending number.
• Tax. 401(k) contributions are pre-tax, and withdrawals are taxed. The balance here is the pre-tax total, not what lands in a checking account. The Roth vs. Traditional IRA calculator is the place to weigh pre-tax against Roth treatment for the same dollars.
• The account boundary. A 401(k) is one account. A household’s retirement picture includes it alongside IRAs, taxable brokerage, and Social Security.

None of these make the projection wrong; they make it a projection. The disciplined way to use it is to re-run it when salary, contribution, or match changes — the same way a savings goal timeline gets re-run when a deadline or deposit moves.

How to use this calculator

• Current age and retirement age set the years of growth. The gap is the whole engine of the projection: 35 years of compounding turns modest deposits into most of the final balance.
• Annual salary is the base for both the contribution and the match cap. The 50/30/20 budget calculator is the place to find a contribution rate you can actually sustain, and if you are paid by the hour, the hourly to salary calculator produces the annual salary this percentage applies to.
• Contribution (% of salary) is the lever you control directly. At the default inputs, every percentage point of salary is $800 a year.
• Employer match (% of contribution) and match cap (% of salary) encode your plan’s formula — the two figures on the benefits summary page.
• Expected return is the nominal, after-fee rate you reasonably expect. 7% is the historical ballpark for a diversified equity portfolio.
• Inflation converts the projection into today’s dollars. 3% is the long-run US average.

The currency selector changes symbols only — figures are not converted by an exchange rate. The projection itself is currency-agnostic math.

The 401(k) projection and the FIRE number are two halves of one plan: this calculator says what the account will have, and the FIRE calculator says what it needs. When the first number clears the second, the gap between them is the margin you can afford to spend — or the reason to keep saving.