401(k) Growth Calculator
Project your 401(k) balance at retirement, including your contribution, employer match, and compound growth.
What this calculator does
Projects your 401(k) balance at retirement from your current balance, your ongoing contribution, and your employer's matching contribution, then shows how much of your final balance came from each of the three sources: your own money, your employer's match, and investment growth.
Who this is for
Anyone with an employer-sponsored 401(k) who wants to see the real long-term impact of their contribution rate, check whether they're capturing their full employer match, or compare different contribution percentages before adjusting their payroll election.
How this calculator works
Each month, two amounts are added to your balance: your contribution (your salary times your contribution percentage, divided by 12) and your employer's match (calculated on whichever is lower, your contribution percentage or your employer's match cap, since employers only match up to their stated limit, they don't match beyond it). Both amounts then compound monthly at your expected return alongside your existing balance.
Worked example
$50,000 current balance, $80,000 salary, 8% your contribution, employer matching up to 4%, 7% annual return, 25 years to retirement: your contribution is $533/month, your employer adds a further $267/month (since 4% is fully captured within your 8%), for $800/month combined. Over 25 years, that grows to a projected balance of roughly $934,000, made up of about $210,000 from your own contributions, $80,000 from your employer's match, and roughly $644,000 from investment growth alone, more than two-thirds of the total.
What this result means
The employer match breakdown specifically is worth paying attention to: if your contribution percentage is lower than your employer's match cap, you're not receiving the full match, effectively turning down part of your compensation. The calculator only matches up to whichever percentage is lower, so increasing your contribution to at least match your employer's cap is one of the highest-certainty moves in personal finance, since it's an immediate, guaranteed return before any investment growth even happens.
Contributions vs. employer match vs. growth
Run the calculator above to see the breakdown between your contributions, your employer's match, and investment growth.
How your balance grows year by year
Run the calculator above to see your projected balance build year by year.
Common mistakes
- Contributing less than your employer's match cap. This is the single most common and costly mistake, it means turning down free money your employer would otherwise contribute.
- Not adjusting for the 2026 IRS contribution limits. This calculator doesn't cap your inputs against the annual limit ($24,500 standard for 2026, more with catch-up contributions); check you're not planning to contribute more than what's actually allowed.
- Assuming a flat return every single year. Real returns vary year to year, and the actual sequence of good and bad years matters, especially close to retirement.
- Forgetting that a partial match needs converting to an effective percentage. If your employer matches 50 cents per dollar up to 6% of salary, the effective full-match cap for this calculator is 6%, not 3%, since the cap refers to your contribution level, not the dollar amount matched.
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Frequently Asked Questions
Am I leaving free money on the table?
If your contribution percentage is below your employer's match cap, yes. For example, if your employer matches up to 4% of salary and you're only contributing 2%, you're missing out on the other 2% entirely, money your employer would otherwise give you for free.
Does this calculator assume a specific match structure?
It assumes a simple dollar-for-dollar match up to the percentage you enter, the most common structure. Some employers use a partial match instead (like 50 cents per dollar up to 6%), in which case you should enter the effective percentage that structure works out to.
Does this account for the 2026 contribution limits?
No, this calculator projects growth based on the percentages and salary you enter; it doesn't cap your inputs against the 2026 IRS limits ($24,500 standard, higher with catch-up contributions). Check the 2026 401(k) contribution limits guide separately to make sure your planned contribution amount is actually allowed.
Should I contribute more than my employer's match cap?
Often yes, once you're capturing the full match, additional contributions still grow tax-advantaged, and for many people maxing out or getting close to the annual IRS limit is a reasonable goal if cash flow allows it.