How this calculator works
Traditional 401(k) contributions come out before federal income tax and, in most states, before state income tax. So every dollar you put in costs you less than a dollar of take-home pay.
The calculator works out your 2026 federal income tax with and without the contribution, using the standard deduction and your filing status. The difference is your federal saving. State saving uses the rate you enter.
Social Security and Medicare are still charged on your full salary, so the contribution doesn’t reduce them.
Employer match is shown separately: for example, 50% of what you contribute on the first 6% of salary. Contributing at least enough to get the full match is usually the best return available.
The 2026 limit is $24,500 of your own contributions. From age 50 you can add $8,000, and at ages 60 to 63 the catch-up rises to $11,250. If your percentage would go over, contributions stop at the limit.
Worked example
$75,000 salary, paid every two weeks, 6% contribution, 4% state tax, 50% match up to 6%
- Contribution: 6% of $75,000 = $4,500 a year, or $173.08 per paycheck.
- Federal tax saved: $990 (22% bracket). State tax saved: $180.
- Take-home pay falls by only $3,330 a year, or $128.08 per paycheck.
- With the $2,250 employer match, $6,750 goes into the 401(k) each year.
Questions people ask
How much should I contribute to my 401(k)?
At minimum, enough to get the full employer match. Beyond that it depends on your other goals, but many planners suggest aiming for 10% to 15% of pay including the match.
What is the 401(k) limit for 2026?
$24,500 for your own contributions, plus an $8,000 catch-up from age 50, or $11,250 instead for ages 60 to 63. Employer contributions are counted separately.
Should I choose traditional or Roth?
Traditional saves tax now and is taxed when you withdraw; Roth is taxed now and withdrawn tax-free later. Roth contributions reduce your paycheck by the full amount. Many people split between them.
Do 401(k) contributions lower local taxes?
It depends. Some local taxes, such as Kentucky occupational taxes and Philadelphia’s wage tax, are charged on pay before 401(k) contributions, so they don’t go down.
Sources
Last reviewed October 2, 2026