401(k) Contribution Calculator
Project your retirement nest egg with employer match and IRS 2025 limits.
How 401(k) Contributions Work
A 401(k) is an employer-sponsored retirement account that lets you invest a portion of your paycheck before taxes. The money grows tax-deferred, meaning you pay income tax only when you withdraw it in retirement. For many Americans, maxing out their 401(k) — especially the employer match — is the single most powerful wealth-building tool available.
Contribution Limits (IRS 2025)
- Under age 50: $23,500 per year of your own contributions
- Age 50 and older: $31,000 per year (includes $7,500 catch-up contribution)
- Total combined limit (you + employer): $70,000 ($77,500 with catch-up)
These limits rise most years to keep pace with inflation. Contributing above the limit is not allowed and, if it happens by mistake, the excess must be withdrawn to avoid penalties.
Employer Match: Free Money
Many employers match a percentage of what you contribute, up to a set cap. A typical match is "100% up to 6% of salary" — meaning if you contribute 6% of your paycheck, your employer kicks in another 6%. Over a 30-year career, this match alone can add hundreds of thousands of dollars to your retirement balance.
Rule of thumb: Always contribute at least enough to capture the full employer match. Anything less is leaving free money on the table.
Traditional vs. Roth 401(k)
Most employers offer both options:
- Traditional: Contributions are pre-tax, reducing your current taxable income. You pay tax on withdrawals in retirement.
- Roth: Contributions are after-tax, but qualified withdrawals (including all earnings) are tax-free.
If you expect to be in a higher tax bracket in retirement — or you're early in your career — Roth is often the better choice. If you're in peak earning years and want a tax break now, Traditional may win.
The Power of Compound Growth
The biggest driver of your retirement balance isn't how much you contribute — it's how long your money compounds. A 25-year-old contributing $500/month with a 7% average return will retire with roughly $1.2 million. The same contribution started at age 40 grows to only about $340,000. Every decade of delay roughly halves your final balance.
The 4% Rule
A widely cited retirement guideline says you can safely withdraw about 4% of your portfolio each year in retirement without running out of money over 30 years. So a $1 million balance supports roughly $40,000/year, or $3,333/month. This calculator uses that rule to estimate your monthly retirement income.
Tools to Optimize Your 401(k)
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Frequently Asked Questions
At minimum, contribute enough to get the full employer match — this is immediate 50–100% return on your money. Beyond that, financial planners commonly recommend 10–15% of your gross salary for retirement. If you start late, you may need to save 20%+ to catch up.
Excess contributions are taxable in the year you made them and again when withdrawn — essentially double-taxed. Most payroll systems stop contributions automatically once you hit the limit, but if you change jobs mid-year, track the combined total across employers to avoid going over.
If you're early in your career and expect higher income later, Roth is usually better — you lock in today's lower tax rate. If you're near peak earnings and want a deduction now, Traditional wins. Many experts recommend splitting contributions between both for tax diversification.
The S&P 500 has averaged about 10% annualized over the past century, roughly 7% after inflation. For conservative planning, use 6–7%. For aggressive assumptions, 8–9%. Remember: past performance doesn't guarantee future results, and fees can drag returns by 0.5–1.5% per year.
Withdrawals before age 59½ typically incur a 10% early-withdrawal penalty plus ordinary income tax. Exceptions exist for certain hardships, medical expenses, first-time home purchases (up to $10,000), and periodic payments under IRS Rule 72(t). 401(k) loans are also available at some employers — you pay yourself back with interest, but the loan must be repaid quickly if you leave the job.
You have four options: leave it with the former employer, roll it into your new employer's 401(k), roll it into an IRA, or cash out (not recommended — you'll pay taxes and penalties). Rolling to an IRA usually gives the widest investment choice and lowest fees. Direct rollovers avoid withholding and simplify paperwork.
Yes. 401(k) assets are held in trust by a separate custodian and are legally protected from your employer's creditors under ERISA. The exception is if the plan itself held your employer's own stock and that stock crashed — diversification matters.