401(k) Calculator
See how your 401(k) contribution changes your paycheck today, and how your balance could grow by the time you retire, using 2026 IRS limits and current federal tax brackets.
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Retirement growth projection
How your balance could grow if you keep contributing at this rate every year until retirement.
How this calculator works
Your 401(k) contribution reduces your paycheck two ways depending on the type you pick. A traditional contribution comes out before federal income tax is calculated, so it lowers your taxable wages today. A Roth contribution comes out after tax, so it doesn’t shrink your federal tax bill now, but qualified withdrawals in retirement owe nothing. Either way, Social Security and Medicare are calculated on your full gross pay, since 401(k) contributions don’t reduce FICA wages.
The growth projection assumes your salary, contribution percentage, and employer match stay constant every year until retirement, and that returns compound annually at the rate you enter. Real markets don’t move in a straight line, and IRS contribution limits and your own salary will likely change over time, so treat this as a directional estimate, not a guarantee.
Paycheck impact
Your contribution percentage is applied to your salary, capped at the 2026 IRS elective deferral limit for your age, then run through federal tax and FICA.
Employer match
Calculated as your match rate times whichever is smaller: your contribution percentage or the match limit you set. This amount doesn’t reduce your paycheck.
Compounding growth
Each year, your contributions and employer match are added to your balance, then the whole balance grows at your expected annual return until your retirement age.
2026 IRS 401(k) contribution limits
| Age | Employee Elective Deferral Limit |
|---|---|
| Under 50 | $24,500 |
| 50 to 59, or 64 and older | $32,500 ($24,500 + $8,000 catch-up) |
| 60 to 63 | $35,750 ($24,500 + $11,250 super catch-up) |
Source: IRS Notice 2025-67, announced November 13, 2025. The combined employee and employer contribution limit for 2026 is $72,000 (higher with catch-up contributions), and only compensation up to $360,000 can be counted toward contributions.
Frequently asked questions
Traditional or Roth 401(k), which one lowers my taxes more right now?
Traditional contributions reduce your taxable wages this year, so your paycheck’s federal withholding drops immediately. Roth contributions don’t reduce this year’s tax bill, but the trade-off is tax-free withdrawals later, which can be worth more if you expect to be in a higher tax bracket in retirement.
Does my 401(k) contribution reduce my Social Security or Medicare tax?
No. Both traditional and Roth 401(k) contributions are still subject to Social Security and Medicare tax. Only federal (and often state) income tax withholding is affected, and only for traditional contributions.
Should I contribute enough to get the full employer match?
Most financial guidance treats the full employer match as a baseline, since turning it down usually means leaving guaranteed money on the table. Whether to contribute beyond that depends on your other goals, like an emergency fund or high-interest debt.
What happens if I contribute more than the IRS limit?
Excess contributions need to be withdrawn by a tax deadline set by the IRS or they can be taxed twice, once when contributed and again when withdrawn. This calculator caps your contribution at the 2026 limit for your age automatically.
Does this calculator account for state income tax?
No, this tool covers federal tax and FICA only. Use one of our state-specific paycheck calculators alongside this one to see the full picture for your state.