Personal Information
Enter your age and salary details
Your Contributions
Set your contribution rate and current balance
Employer Match
Configure employer matching details
Growth Assumptions
Set expected returns and salary growth
Historical S&P 500 average: ~10% (7% inflation-adjusted)
Projected Growth
Visualize your 401(k) growth over time
Where Your Money Comes From
Breakdown of your retirement savings
$453,466
Your Contributions
20.1% of total
$136,040
Employer Match
Free money!
$1,636,026
Investment Growth
72.7% of total
Year-by-Year Projection
Detailed annual breakdown
| Age | Your Contrib. | Employer Match | Growth | Balance |
|---|---|---|---|---|
| 35 | $8,441 | +$2,532 | +$5,950 | $96,438 |
| 40 | $9,786 | +$2,936 | +$13,087 | $206,409 |
| 45 | $11,344 | +$3,403 | +$23,853 | $371,982 |
| 50 | $13,151 | +$3,945 | +$39,828 | $617,343 |
| 55 | $15,246 | +$4,574 | +$63,248 | $976,704 |
| 60 | $17,674 | +$5,302 | +$97,273 | $1,498,383 |
| 65 | $20,489 | +$6,147 | +$146,360 | $2,250,531 |
Impact of Contribution Rate
Compare different contribution scenarios
5% contribution
$1,411,309
+$113,366 match
10% contribution
$2,250,531
+$136,040 match
15% contribution
$2,962,508
+$136,040 match
20% contribution
$3,504,474
+$136,040 match
What If I Changed My Contribution?
See how adjusting your contribution rate affects your retirement
Balance at Retirement
$2,250,531
Retirement Savings Milestones
100.0% complete
$2,250,531
of $1,875,000
$100K
$100,000
First major milestone!
$250K
$250,000
Quarter millionaire!
$500K
$500,000
Halfway to a million!
$1 Million
$1,000,000
Millionaire status!
25x Salary
$1,875,000
Full retirement goal (4% rule)
Goal Achieved!
Congratulations on reaching your target!
$100K
$100,000
$250K
$250,000
$500K
$500,000
$1 Million
$1,000,000
25x Salary
$1,875,000
Your 401(k) Insights
3 insights based on your inputs
Your Early Start Advantage
Starting now instead of 5 years later could mean $752,148 more at retirement thanks to compound growth!
Consider Increasing Contributions
Financial experts recommend saving 15% of income for retirement. Small increases now can make a big difference later.
Maximizing Employer Match!
You're getting the full employer match of $2,250 per year. That's free money!
401(k) Health Score
Based on your financial inputs
Score Breakdown
Improvement Areas
Contribution Rate
Try to increase from 10 to 15
Strong: Progress to Goal
You're doing great with 120.028%!
Withdrawal Impact Analysis
What a withdrawal actually costs you
Federal + state bracket for the withdrawal year
Traditional 401(k) withdrawals are ordinary income. Penalty-free from age 59½; Rule 72(t) substantially-equal-periodic payments and certain hardships are exceptions. Roth contributions can come out tax-free any time — earnings cannot. The "lost growth" line assumes the money compounds for 35 more years — the real cost of cashing out early.
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Frequently Asked Questions
What is a 401(k) plan?
A 401(k) is an employer-sponsored retirement savings plan that allows employees to contribute pre-tax or Roth (after-tax) dollars from their paycheck. Many employers offer matching contributions up to a certain percentage, essentially providing free money toward your retirement.
What is the 401(k) contribution limit for 2024?
For 2024, the employee contribution limit is $23,000. If you're 50 or older, you can make an additional catch-up contribution of $7,500, bringing your total to $30,500. The combined limit for employee and employer contributions is $69,000 (or $76,500 with catch-up).
What is employer matching?
Employer matching is when your employer contributes money to your 401(k) based on your contributions. A common match is 50% of your contribution up to 6% of salary. So if you earn $100,000 and contribute 6% ($6,000), your employer adds $3,000. This is essentially free money.
Traditional vs Roth 401(k): Which is better?
Traditional 401(k) contributions are pre-tax, reducing your current taxable income but taxed on withdrawal. Roth 401(k) contributions are after-tax, providing tax-free withdrawals in retirement. Choose Roth if you expect higher taxes in retirement, Traditional if you expect lower taxes.
When can I withdraw from my 401(k)?
You can start penalty-free withdrawals at age 59½. Early withdrawals typically incur a 10% penalty plus income taxes, though exceptions exist for hardship, disability, or substantially equal periodic payments (Rule 72t). Required minimum distributions (RMDs) begin at age 73.
How much should I contribute to my 401(k)?
Financial experts recommend contributing at least enough to get your full employer match (otherwise you're leaving free money). Beyond that, aim for 10-15% of income. The ideal amount depends on your age, retirement goals, and other savings.
How this works
Projects 401(k) balance forward using your annual contribution (plus employer match, if any), assumed nominal return, and contribution increase rate. Annual limit is read from the current IRS publication at build time; check the IRS link for the latest year's cap.
What this tool can’t do
- Does not model Roth vs Traditional tax treatment beyond a flat assumed marginal rate.
- No Monte Carlo — the return rate is a deterministic assumption, not a distribution.
When to consult a professional
This is a software engineering tool, not financial advice. Run the math here, then take the result to a certified financial planner, CPA, or your bank before making a decision that materially affects your money.
Sources
- [1]Consumer Financial Protection Bureau (CFPB)Official sourceconsumerfinance.govAccessed Apr 21, 2026
US consumer finance regulator; authoritative on mortgage disclosures, APR rules, credit cards.
- [2]Internal Revenue Service (IRS) — official publicationsOfficial sourceirs.govAccessed Apr 21, 2026
Primary source for US federal tax rules, contribution limits, and standard deductions.
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).