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401(k) Calculator 2025

See how your 401(k) grows — or check if you're maxing out your contributions.

Your 401(k)
$
$
Your annual 401(k) contribution
%
% of your contribution they match
%
They only match up to this % of salary
$
%
Historical S&P 500 avg: ~10% (7% after inflation)
—
2025 contribution limit: $23,500 ($31,000 if 50+). Does not account for taxes on withdrawals.

How to Use This Calculator

Growth tab

Enter your current age, retirement age, current 401(k) balance, and annual contribution. The calculator projects your balance at retirement with compound growth. Expand "More Options" to add an employer match percentage and match limit — this shows how much free money your employer adds on top of your contributions.

Max Out tab

Enter your annual salary and current contribution percentage. The calculator shows how much more you could contribute to hit the IRS annual limit. If you're 50 or older, toggle catch-up contributions to see the higher limit. It also shows the per-paycheck increase needed to max out.

Share your result

Every input is encoded in the URL. Click Share, send the link — they'll see your exact numbers. No re-entering, no screenshots.

The Formula

A 401(k) grows through compound interest on your contributions, employer match, and investment returns. The future value combines your existing balance and recurring contributions:

FV = PV × (1 + r)n + PMT × [(1 + r)n − 1] / r

Where PV = current balance, PMT = annual contribution (yours + employer match), r = annual rate of return, n = years until retirement.

Employer match

Employer Match = min(your_contribution, salary × match_limit%) × match_%

For example, if your employer matches 50% of contributions up to 6% of salary, they contribute up to 3% of your salary each year — but only if you contribute at least 6%.

Example

Mike — planning for retirement at 65

Mike is 30 years old, earns $75,000/year, and has $25,000 in his 401(k). He contributes $6,000/year. His employer matches 50% of contributions up to 6% of salary. He expects a 7% average annual return.

Inputs

Current age30
Retirement age65
Current balance$25,000
Annual contribution$6,000
Employer match50% up to 6% of salary
Annual return7%

Breakdown at 65

Employer match/year$2,250 (50% of $4,500 limit)
Total annual contribution$8,250 ($6,000 + $2,250)
Your contributions (35 yrs)$210,000
Employer contributions$78,750
Investment growth~$850,000+
Projected balance at 65~$1,140,000+

Most of Mike's final balance comes from compound growth — not his contributions. Starting at 30 gives him 35 years for compounding to do the heavy lifting. The employer match adds over $78K in free money.

FAQ

At minimum, contribute enough to get your full employer match — that's free money you'd otherwise leave on the table. Beyond that, aim for 15% of your gross income (including the match). If you can't hit 15% right away, increase your contribution by 1% each year until you get there.
The 2025 401(k) employee contribution limit is $23,500. If you're 50 or older, you can make an additional catch-up contribution of $7,500, bringing your total to $31,000. These limits apply to your employee deferrals only — employer match contributions don't count toward this cap.
Traditional 401(k) contributions are pre-tax — they lower your taxable income now, but you pay income tax on withdrawals in retirement. Roth 401(k) contributions are after-tax — no tax break today, but qualified withdrawals in retirement are completely tax-free. Choose Traditional if you expect to be in a lower tax bracket in retirement; choose Roth if you expect your rate to stay the same or go up.
Yes. Once you turn 50, you're eligible for catch-up contributions ($7,500 extra in 2025). Beyond that, save as aggressively as you can — even 20-25% of income if possible. Consider delaying retirement by a few years, which gives your money more time to compound and reduces the number of years you need to fund. Use the Max Out tab to see exactly how much room you have left under the limit.
A common assumption is 7% for a real (inflation-adjusted) return, or 10% for a nominal return — both based on the long-term average of a diversified stock portfolio. Use 7% if you want your result in today's dollars (more conservative and practical). Use 10% if you want the raw future dollar amount. If you're closer to retirement and hold more bonds, 5-6% may be more realistic.

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