401(k) Growth Calculator
Project your 401(k) to retirement and see exactly how much of it is your money, your employer’s match, and investment growth — with a warning the moment you’re leaving match on the table.
Stacked area chart of 401(k) balance from age 35 to 67. Your contributions, employer match, and investment growth stack to a projected $1,047,414, of which $107,291 is employer match.
Estimates only. Employer-match rules, vesting, and IRS limits vary — confirm with your plan documents. Not investment advice.
For educational use only. This calculator provides estimates based on the assumptions you enter and does not constitute investment, tax, or legal advice. Results are not guarantees of future performance. Consult a qualified professional before making financial decisions.
How the 401(k) calculator works
This calculator projects your workplace retirement plan month by month from today to the age you retire. Each month it applies your assumed investment return to the existing balance, then adds two fresh contributions: yours — a percentage of that month’s salary — and your employer’s match on top. Your salary grows each year by the raise rate you set, so your percentage contribution grows automatically with it. The three ingredients are tracked separately so the chart can show exactly how much of your final balance is money you put in, money your employer added, and growth the market provided.
The employer match is the piece most calculators fumble, so it is worth stating precisely. A match is defined by two numbers: a rate (how many cents per dollar) and a ceiling (the share of salary it applies to). A “50% match up to 6% of salary” means the employer contributes 50 cents per dollar you defer, but only on the first 6% of pay — a maximum employer contribution of 3% of salary. Contribute below 6% and you forfeit part of that free money; contribute above 6% and the match does not grow further, though your own savings do. The formula the model uses each month is employerMatch = salary × min(yourRate, ceiling) × matchRate.
Employee contributions are subject to an annual IRS limit — $23,500 for 2025, plus a catch-up once you turn 50. By default the calculator caps your deferrals at that limit (the employer match is separate and is not counted against it). You can switch the cap off to model “what if I could save more” scenarios. The single most important output is the employer match earned over your career: for a typical saver that runs well into six figures, and it is the clearest argument for never leaving the match on the table.
Every input, explained
Current 401(k) balance
What your workplace plan is worth today — your 401(k), 403(b), or TSP. Do not include IRAs or taxable brokerage accounts; those grow under different rules. If you have old 401(k)s from previous jobs, include them only if you have rolled them into this plan.
Annual salary
Your gross yearly pay. It drives both your percentage contribution and the size of the employer match, so use your steady base salary. If a large share of your pay is variable (bonus, commission), consider whether your plan matches on that too — many do not.
Your contribution
The percent of each paycheck you defer into the plan. This is the lever with the most control: raising it even one point compounds dramatically over decades. The number one rule is to contribute at least up to the match ceiling — anything less is a guaranteed loss. The calculator flags this with a warning the moment your contribution drops below the ceiling.
Employer match (rate and ceiling)
Enter the two numbers from your benefits summary: the match rate and the salary percentage it applies to. Common structures are “50% up to 6%” and “100% up to 3–4%.” If your employer does not match, set the rate to zero — the calculator still projects growth from your own contributions. If your plan has a more complex tiered match, approximate it with the effective rate and ceiling.
Annual raise and return
The raise rate grows your salary and, with it, your percentage contribution. The return is your assumed average annual investment growth. Returns are the least predictable input, so it is worth lowering them a couple of points to see how your projection holds up. Investment fees act like a negative return: a seemingly small 1% expense ratio can consume a meaningful slice of your lifetime balance, so prefer low-cost index funds when your plan offers them.
The math, stated plainly
Working in monthly steps with a monthly-effective return r = (1 + annualReturn)^(1/12) − 1, each month:
yourContribution = (salary ÷ 12) × yourRate, capped at the annual IRS limit if enabled.employerMatch = (salary ÷ 12) × min(yourRate, ceiling) × matchRate.balance = balance × (1 + r) + yourContribution + employerMatch.
Salary itself grows monthly at (1 + raise)^(1/12) − 1. The “match left on the table” is the employer money you would forfeit by contributing below the ceiling, and the calculator compounds those missed dollars forward to show what they would have become by retirement — usually a startling number, because a forfeited match loses decades of growth, not just the cash.
Assumptions and limitations
- Straight-line returns. The model grows your balance at a constant rate; real markets are volatile, and the order of good and bad years matters, especially near retirement.
- The match is assumed fully vested. If your plan has a vesting schedule and you leave early, you could forfeit part of it — check your plan documents.
- The IRS limit is held flat. In reality the limit is periodically raised for inflation; keeping it constant is slightly conservative for high earners in later years. The employer match is not counted against the employee limit here.
- Taxes and fees are not modeled. Traditional 401(k) withdrawals are taxable; fund fees reduce returns every year. Balances shown are pre-tax and pre-fee.
- It is not advice. A projection is a planning tool, not a promise.
Where this fits with your other planning
The 401(k) is usually the engine of a retirement plan, but it is one part of the picture. Once you know your projected balance here, see how it fits the whole with the retirement calculator, which folds in Social Security and other income and tells you whether your total savings will last. If you are weighing pre-tax versus after-tax contributions, the Roth vs. Traditional calculator models both. And to build intuition for why starting early matters so much, the compound interest calculator shows the raw power of reinvested growth.
Frequently asked questions
- How much should I contribute to my 401(k)?
- At an absolute minimum, contribute enough to earn your full employer match — that is free money and an instant return you cannot get anywhere else. Beyond that, a common target is 15% of gross pay including the match. If 15% is out of reach today, raise your contribution by one percentage point each year, ideally timed to a raise so you never feel the cut.
- What does "50% match up to 6%" actually mean?
- It means your employer adds 50 cents for every dollar you contribute, but only on the first 6% of your salary. So if you earn $80,000 and contribute at least 6% ($4,800), your employer adds 3% ($2,400). Contributing more than 6% is fine, but the match stops growing past that ceiling — the extra is all your own money.
- Is the employer match really worth it?
- A 50% match is an immediate, guaranteed 50% return on the matched portion — before any market growth — and a dollar-for-dollar match is an instant 100%. No investment reliably beats that. Passing up the match to pay down low-interest debt or invest elsewhere almost never comes out ahead. Capture the full match first, then optimize the rest.
- What happens if I contribute above the IRS limit?
- Employee 401(k) deferrals are capped each year by the IRS — $23,500 for 2025, with an extra $7,500 catch-up once you turn 50 (and a higher catch-up at ages 60–63). Your payroll system normally stops you at the limit. This calculator can cap deferrals at the limit or, for planning scenarios, let you model contributions above it. The employer match is separate and not counted against this employee limit.
- Does the employer match count toward the contribution limit?
- No. The annual elective-deferral limit applies only to the money you defer from your own paycheck. Employer contributions fall under a separate, much higher overall limit (the Section 415(c) limit on total contributions). For nearly everyone, the employee deferral limit is the one that binds first.
- Should I contribute to a Roth or Traditional 401(k)?
- Traditional contributions lower your taxable income now and are taxed on withdrawal; Roth contributions are made with after-tax dollars and come out tax-free. If you expect a higher tax rate in retirement, Roth tends to win; if lower, Traditional. Many people split the difference. Our companion Roth vs. Traditional calculator models both sides directly.
- What is vesting, and does it affect the match?
- Vesting is how long you must stay before the employer match is fully yours. Some plans vest immediately; others use a schedule (for example, 20% per year over five years). Your own contributions are always 100% yours. If you might leave before you are fully vested, you could forfeit part of the match — check your plan documents, because this calculator assumes the match is fully vested.
- How is this different from an IRA?
- A 401(k) is an employer-sponsored plan with much higher contribution limits and, crucially, the employer match — an IRA has neither. IRAs, however, usually offer more investment choices and can be opened by anyone with earned income. Many people use both: contribute to the 401(k) up to the match, then an IRA, then back to the 401(k).
- Why does my projected balance assume my contribution grows?
- Because you contribute a percentage of salary, your contribution automatically rises as your salary grows with raises. That compounding of a growing contribution on top of investment growth is a big part of why starting early matters so much. If you prefer a flat dollar amount, set your raise rate to zero to approximate it.
- Is a 6–7% return realistic for a 401(k)?
- It is a reasonable long-run nominal assumption for a diversified stock-and-bond portfolio, though real returns are volatile and no year is average. Fees matter too: a 1% expense ratio quietly eats a large share of lifetime growth, so favor low-cost index funds where available. Try a lower return in the calculator to see how sensitive your balance is.