Putting money in a traditional 401(k) feels like giving up spending power today. It does, but less than the sticker amount suggests. Because a traditional contribution comes out of your pay before federal income tax, every dollar you save also shaves a slice off your tax bill. The result is that a $10,000 contribution might reduce your take-home pay by only $7,800. This is the mechanic that makes retirement saving cheaper than the headline number, and it is worth understanding before you set your 2026 payroll percentage.
The 2026 contribution limits
The IRS raised the elective deferral limit for 2026. If you are under 50, you can put up to $24,500 of your own pay into a 401(k), 403(b), most 457 plans, or the federal Thrift Savings Plan, up from $23,500 in 2025. Savers aged 50 and over get a catch-up of $8,000 on top, for $32,500. A special higher catch-up of $11,250 applies to people who turn 60, 61, 62, or 63 during the year, so those savers can reach $35,750. The figures are set out in the IRS 2026 retirement plan limits announcement and IRS Notice 2025-67.
These limits cover only what you contribute from your own paycheck. Employer matching and profit sharing sit under a separate, much higher combined cap. A traditional IRA is a different account with its own limit, which rose to $7,500 for 2026, or $8,600 with the age-50 catch-up.
Traditional versus Roth: which dollars are pre-tax
A traditional 401(k) contribution is pre-tax. It lowers your taxable wages now, and you pay income tax later when you withdraw in retirement. A Roth 401(k) contribution is the reverse: you pay tax now, the money grows, and qualified withdrawals come out tax-free. The take-home discount described in this article applies to traditional contributions only, because those are the dollars that reduce this year’s tax. Roth contributions cost you the full amount today in exchange for tax-free growth.
Which is better depends on whether you expect a higher or lower tax rate in retirement than you face now. Neither is a trick; they just move the tax to different decades.
Why a contribution costs less than it looks
The United States taxes income in bands, so the last dollars you earn sit in your highest, or marginal, bracket. A traditional 401(k) contribution is subtracted from the top of your taxable income, so it removes dollars that would have been taxed at that marginal rate. The tax you avoid is the contribution multiplied by that rate.
Say your marginal rate is 22 percent. Contributing $10,000 removes $10,000 that would have been taxed at 22 percent, saving $2,200. The money still leaves your paycheck, but $2,200 of it would have gone to the IRS anyway, so your actual take-home only drops by $7,800. That $7,800 is the true out-of-pocket cost of a $10,000 retirement balance. You can sanity-check the arithmetic with the percentage calculator.
FICA does not get the discount
One common misunderstanding is that a 401(k) contribution avoids all payroll deductions. It does not. Social Security and Medicare taxes, together called FICA, are charged on your gross wages before the 401(k) subtraction, so your contribution still pays the 6.2 percent Social Security tax (up to the $184,500 wage base) and the 1.45 percent Medicare tax. Only federal and, where it applies, state and local income tax are reduced. That is still the large majority of the benefit for most earners, but it is worth knowing the FICA line on your payslip will not move when you raise your deferral.
Worked example: $80,000 single filer maxing out in 2026
Take a single filer earning $80,000 who takes the standard deduction of $16,100 and decides to contribute the full $24,500.
Without any 401(k) contribution, taxable income is $63,900 and federal income tax works out to $8,770. Contributing $24,500 drops taxable income to $39,400. The tax on that is $1,240 in the 10 percent band plus $3,240 in the 12 percent band, a total of $4,480.
So the contribution cuts the federal tax bill from $8,770 to $4,480, a saving of $4,290. The full $24,500 does leave the paycheck, but $4,290 of it was tax you would have paid anyway. Your take-home therefore falls by $24,500 minus $4,290, which is $20,210. Put another way, each dollar sitting in the retirement account cost you about 82 cents of spending money. FICA is unchanged at $6,120, because payroll tax still applies to the full $80,000. To see the per-paycheck version of this for your own salary and state, run the paycheck calculator.
What a $10,000 contribution saves at different salaries
Because the saving depends on your marginal band, the same $10,000 traditional contribution is worth more the higher your income climbs. The table below is for a single filer in 2026 taking the standard deduction, before any state tax (state income tax, where it applies, adds further savings on top).
| Gross salary | Top marginal band | Federal tax saved on $10,000 | Net cost of the $10,000 |
|---|---|---|---|
| $50,000 | 12% | $1,200 | $8,800 |
| $70,000 | 22% to 12% | $1,550 | $8,450 |
| $90,000 | 22% | $2,200 | $7,800 |
| $120,000 | 22% | $2,200 | $7,800 |
| $150,000 | 24% | $2,400 | $7,600 |
| $220,000 | 32% to 24% | $2,570 | $7,430 |
The $70,000 and $220,000 rows straddle two bands: the first slice of the contribution comes out of the higher band and the rest out of the one below, which is why the saving is not a round percentage. The bracket thresholds used here are the 2026 single-filer figures from the IRS inflation adjustments for tax year 2026.
Do not leave the employer match behind
Before you fret over maxing out, the highest-return move is capturing your full employer match. A typical match of 50 cents on the dollar up to 6 percent of pay is an immediate 50 percent return on those dollars, on top of the tax break. If your budget cannot reach the $24,500 limit, contribute at least enough to collect every matched dollar first, then decide how much further to stretch. A savings rate calculator can show what share of take-home you are actually banking once the match is counted, and the compound interest calculator shows how those contributions grow over a career.
FAQ
Does a 401(k) contribution really lower my tax bill?
Yes, for a traditional contribution. The money is taken from your pay before federal income tax, so it reduces your taxable income dollar for dollar. The tax you avoid equals the contribution times your marginal rate, which is why a $10,000 traditional contribution can reduce take-home by well under $10,000.
What is the 2026 401(k) contribution limit?
It is $24,500 for savers under 50. Those 50 and over can add an $8,000 catch-up for $32,500, and savers who turn 60 to 63 during the year get a larger $11,250 catch-up, reaching $35,750. Employer contributions are separate and do not count toward these employee limits.
Does contributing to a 401(k) reduce my Social Security and Medicare tax?
No. FICA taxes are charged on gross wages before the 401(k) deduction, so your 6.2 percent Social Security and 1.45 percent Medicare come out of the full amount. Only income tax is reduced by a traditional contribution.
Should I choose traditional or Roth?
Traditional gives you the tax break now and taxes withdrawals later, while Roth is taxed now and tax-free later. Pick traditional if you expect a lower tax rate in retirement than today, and Roth if you expect a higher one. Many savers split the difference across both.
Is maxing out always the right move?
Not necessarily. Capturing the full employer match is almost always worth it, but beyond that, high-interest debt and an emergency fund often deserve priority. Once those are handled, raising your deferral toward the limit is one of the most tax-efficient ways to build wealth. The FIRE number calculator can help you set a target worth saving toward.