401(k) Growth Calculator
Project your 401(k) balance at retirement, including your contributions, employer match, and compound growth.
How does 401(k) growth actually work?
Every paycheck, a percentage of your salary goes into your 401(k) automatically, and many employers add a matching contribution on top — often described as "free money" because it's compensation you'd otherwise leave on the table. Both your contributions and your employer's match are then invested, typically in mutual funds or target-date funds, and grow through compound returns over decades. This calculator models that process month by month: it takes your current balance, adds your monthly contribution plus employer match, and applies your expected rate of return every single month until retirement, so the growth compounds on itself just like a real account.
Why employer match matters so much
If your employer matches 100% of contributions up to 3% of salary and you only contribute 2%, you're leaving a full percentage point of free money unclaimed every year — and losing decades of compound growth on it. Most financial planners recommend contributing at least enough to capture the full employer match before considering other savings goals, since no other investment offers a guaranteed 100% instant return. Use the calculator above to see exactly how much that match adds to your final balance versus contributing without it.
What this calculator doesn't account for
This tool assumes a constant contribution rate, salary, and rate of return every year, which real markets never actually deliver — returns vary widely year to year even if they average out over long periods. It also doesn't factor in contribution limit caps set by the IRS (which change annually and increase with age-based catch-up contributions), vesting schedules on employer match, or required minimum distributions later in life. Treat the result as a directional estimate for planning purposes, not a guarantee, and revisit your numbers periodically as your salary and goals change.
Frequently Asked Questions
How much should I contribute to my 401(k)?
A common starting point is to contribute at least enough to get your full employer match, since that's essentially a guaranteed return on your money. From there, many planners suggest working toward saving 10-15% of your income total (including the match) for retirement.
What does "100% match up to 3%" actually mean?
It means your employer contributes one dollar for every dollar you contribute, up to a maximum of 3% of your salary. If you contribute 3% or more, you get the full 3% match; if you contribute less, say 2%, your employer only matches that 2% — you don't automatically get the full cap.
Does this calculator account for annual 401(k) contribution limits?
No — this tool is a simplified projection based on a constant contribution percentage of your salary. The IRS sets annual dollar limits on employee contributions that change yearly and increase for those 50 and older through catch-up contributions, so very high earners or high contribution rates may hit that cap in reality even though this calculator doesn't model it.
What rate of return should I use?
Long-term historical average annual stock market returns are often cited around 7-10% before inflation, though your actual return depends heavily on your investment mix and market conditions. Many planners use a more conservative 6-7% for long-range retirement planning to account for fees and down years.
Is employer match considered "free money"?
Yes, in the sense that it's compensation on top of your salary that you only receive if you contribute enough to earn it. Failing to contribute enough to get the full match is often described as leaving free money on the table, since no other typical investment offers a guaranteed 100% immediate return.
What's the difference between a traditional and Roth 401(k)?
A traditional 401(k) is funded with pre-tax dollars, lowering your taxable income now, but withdrawals in retirement are taxed as ordinary income. A Roth 401(k) is funded with after-tax dollars, so there's no upfront tax break, but qualified withdrawals in retirement are completely tax-free.
How accurate is this 401(k) projection?
It's a directional estimate, not a guarantee. Real markets don't return a steady percentage every single month — they fluctuate significantly year to year — and this tool assumes your salary, contribution rate, and employer match stay constant the entire time, which rarely happens exactly in real life.
Should I increase my 401(k) contribution every year?
Many people gradually increase their contribution rate with each raise, sometimes called "auto-escalation," since it grows your retirement savings without feeling like a cut to your current take-home pay. Try adjusting the contribution percentage above to see how even a 1-2% annual increase compounds over time.