How to use the 401(k) calculator
- Enter your current age, retirement age and salary, plus the raise you expect each year.
- Set your contributions as a percentage of pay: traditional (pre-tax), Roth (after-tax) or both. Leave the catch-up box ticked if you plan to save above the normal limit from age 50.
- Pick your employer match from the list or type your plan's formula into the two tiers. For example, "100% of the first 3%, then 50% of the next 2%".
- Enter your current balance, the annual return you expect and inflation.
- Read the projected balance, in future dollars and in today's dollars, and where it comes from. Open Paycheck settings to choose your filing status, pay frequency and state for the paycheck comparison.
How the projection works
For each year until retirement, the calculator grows your salary by the raise you entered and works out your contribution as a percentage of pay. It then applies the 2026 IRS limits. In 2026 you can contribute up to $24,500 of your own pay (traditional and Roth together). From age 50 you can add a $8,000 catch-up, and at ages 60 to 63 the catch-up is $11,250 instead. Your contributions plus your employer's, not counting catch-ups, cannot exceed $72,000 (the section 415(c) limit), and the plan counts at most $360,000 of pay. When a limit cuts your contribution, the year-by-year table marks it.
The employer match is calculated on the share of pay you actually contribute, tier by tier. Contributions are spread evenly over the year and grow at the monthly equivalent of your annual return. The "today's dollars" figure divides each balance by the inflation you entered, so you can compare it with prices now. Limits normally rise with inflation; the calculator keeps them at 2026 levels, which is a conservative assumption.
From 2026, if your wages from the employer last year were over $150,000, catch-up contributions must go in as Roth. The paycheck comparison takes this into account.
Worked example
A 30-year-old earning $65,000 with 3% yearly raises puts 6% into a traditional 401(k). The employer matches 50% of contributions up to 6% of pay, the balance today is $25,000, and the return is 6% a year. In year one they save $3,900 and the employer adds $1,950. By age 67 the projected balance is about $1,400,451: $25,000 starting balance, $258,079 of their own contributions, $129,040 of employer match and $988,331 of investment growth. At 2.5% inflation that is about $561,675 in today's dollars.
On the paycheck side, single with no state income tax: the $3,900 traditional contribution cuts 2026 federal income tax by $468 (it comes off income taxed at 12%). Take-home pay therefore falls by $3,432 a year, about $132 per biweekly paycheck, not the full $150 that goes into the account.
What can make your result different
- Investment returns are never steady. A few bad years near retirement matter more than the average.
- Fees reduce your net return; enter the return after fund expenses.
- Vesting: employer contributions may only become yours after a number of years of service.
- Plan rules differ: some employers match each paycheck without a year-end true-up, some cap the match on catch-ups, and some add profit-sharing contributions.
- Taxes in retirement: traditional balances are taxed when withdrawn; qualified Roth withdrawals are tax-free. The projection shows balances before tax.
Related calculators
See your full take-home pay with the US salary calculator or the paycheck calculator, which also handle HSA and other pre-tax deductions. Compare job offers, including their 401(k) match, with the salary comparison calculator. Paying off high-interest debt can come first; plan it with the debt payoff calculator. All tools are listed under salary and money calculators.
Frequently asked questions
What is the 401(k) contribution limit for 2026?
$24,500 of employee contributions, traditional and Roth combined. Workers aged 50 and over can add an $8,000 catch-up, and those aged 60 to 63 can add $11,250 instead. Employee plus employer contributions are limited to $72,000, not counting catch-ups.
How does an employer 401(k) match work?
The employer adds money based on what you contribute. With a "50% up to 6%" match, if you contribute 6% of pay the employer adds 3%; if you contribute 4% it adds 2%. Contributing at least enough to get the full match is a common first savings goal.
Should I choose a traditional or a Roth 401(k)?
Traditional contributions lower your taxable income now and are taxed when you withdraw them. Roth contributions are taxed now, and qualified withdrawals are tax-free. If you expect a higher tax rate in retirement, Roth tends to win; if lower, traditional. Many people split between the two. Enter both percentages to see the balance and the paycheck effect.
How much does a 401(k) contribution reduce my paycheck?
Less than the amount you contribute, if it is traditional, because it lowers your federal and usually your state income tax. Social Security and Medicare are still taken on it. The paycheck impact table shows the difference for your salary, filing status and state.
What return should I assume?
There is no right answer: it depends on your investments and is never guaranteed. Try several rates, for example a cautious and an optimistic one, and look at the result in today's dollars.
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