401(k) Paycheck Impact Calculator

How the 401(k) Paycheck Impact Calculator: Traditional vs Roth Works

Deciding how much to contribute to a 401(k), and whether to use traditional or Roth, changes your paycheck by a different amount than the contribution itself, because traditional contributions lower your taxable wages today. This calculator shows the real reduction in take-home pay for a given contribution percentage, compares traditional and Roth, and adds in an estimated employer match.

Enter your salary, contribution percentage, contribution type, and your employer's match percentage to see the effect on your paycheck.

Traditional versus Roth: the paycheck difference

A traditional 401(k) contribution comes out of your pay before federal income tax (and usually state tax) is calculated, so contributing $100 might only reduce your take-home pay by $70 to $78, depending on your tax bracket, because the rest is tax you would have paid anyway. A Roth 401(k) contribution comes out after tax, so contributing $100 reduces your take-home pay by the full $100.

Neither type reduces the Social Security and Medicare wages used for FICA tax; both are withheld on your full salary regardless of 401(k) elections. The real question with traditional versus Roth isn't the paycheck cost today, but whether you expect to be in a higher or lower tax bracket when you eventually withdraw the money in retirement.

Getting the full employer match

Many employers match a percentage of your salary, often 50 cents to a dollar for each dollar you contribute, up to a certain percentage of pay, commonly 3% to 6%. If you contribute less than your employer's match threshold, you're leaving money on the table: it's essentially a guaranteed return that isn't available anywhere else. Contributing at least enough to capture the full match is one of the highest-value financial moves most workers can make.

This calculator adds the estimated match on top of your own contribution to show the total amount going into your account each year, separate from the paycheck impact, which only reflects your own contribution.

When Roth might make more sense

Roth contributions are generally more attractive early in your career when your income, and tax bracket, are likely lower than they'll be later, since you pay tax now at a lower rate in exchange for tax-free growth and withdrawals later. They can also make sense if you expect tax rates in general to rise, or if you want to reduce required minimum distributions in retirement, since Roth 401(k) balances (unlike traditional) aren't subject to RMDs after a 2024 rule change for the original account holder.

Many plans allow splitting contributions between traditional and Roth, which lets you hedge against uncertainty about future tax rates rather than committing entirely to one approach.

Other paycheck effects to check

A higher 401(k) contribution percentage lowers your take-home pay, which can affect your ability to qualify for a mortgage if a lender looks at gross versus net income differently, or affect calculations for other benefits tied to reported wages. It's worth modeling a planned contribution increase against your monthly budget using the actual reduced take-home figure this calculator shows, not just the gross contribution amount, before committing to a higher percentage.

Vesting and leaving a job early

Your own 401(k) contributions are always fully yours, but employer matching contributions often vest over time, meaning you only keep them if you stay long enough, commonly on a schedule of immediate, graded over 2 to 5 years, or a cliff after a set period. If you're planning to leave a job soon, check your plan's vesting schedule before assuming you'll keep the full match shown in this calculator, since unvested employer contributions are forfeited if you leave before they vest.

Automatic escalation and target-date funds

Many plans now offer automatic escalation, which raises your contribution percentage by 1% each year, often up to a cap such as 10% or 15%, so you save more over time without having to remember to change it yourself. If your plan offers this, opting in is one of the easiest ways to steadily increase retirement savings while giving yourself time to adjust to each small paycheck reduction rather than one large jump.

Most 401(k) plans default new enrollees into a target-date fund matched to an estimated retirement year, which automatically becomes more conservative as that date approaches. This doesn't change the paycheck math shown by this calculator, but it's worth understanding what your contributions are actually invested in, since the investment choice matters far more to your long-term outcome than the traditional-versus-Roth decision alone.

Contribution limits for 2026

The elective deferral limit for 401(k) plans is $24,500 for 2026, combined across traditional and Roth employee contributions. Workers age 50 and older can make additional catch-up contributions, and a higher catch-up limit applies for those aged 60 to 63 under recent law changes. Employer matching contributions do not count against your personal deferral limit, though there is a separate, higher combined limit for total contributions from both you and your employer.

If you contribute a flat percentage of pay, watch that you don't exceed the annual dollar limit before the end of the year, since some plans stop your contributions once you hit the limit, which can also stop your employer match early in some designs unless the plan uses a true-up feature.

Worked example

A single filer earning $65,000 contributes 6% traditionally, or $3,900 a year. This lowers taxable income and saves roughly 22 cents of federal tax on part of that amount plus 5 cents of state tax on all of it, for total tax savings of around $850 to $900, so take-home pay falls by only about $3,000 to $3,050 instead of the full $3,900. If the employer matches 3% ($1,950), the total going into the account is about $5,850 a year for a real paycheck cost of roughly $3,000.

If the same $3,900 were contributed as Roth instead, take-home pay would fall by the full $3,900, but withdrawals in retirement, including all the growth, would be tax-free rather than taxable.

401(k) Paycheck Impact results at a glance

These are the calculator's results at different values of annual salary, with every other input left at the example values above (the bold row is the example). Use them to see how quickly the result changes before entering your own numbers.

How contribution type changes the result

The same example with each contribution type option:

How filing status changes the result

The same example with each filing status option:

The same example at different state tax rates

State income tax is the input that varies most between readers. Nine states charge 0% on wages, flat-tax states charge one rate, and progressive states charge more at higher incomes. Here is the example at five effective state rates; for your exact state rules, use the state paycheck calculators.

What common contribution rates cost per paycheck

For a single filer earning $65,000 paid every two weeks, before state tax. A traditional contribution costs less than its face value because it lowers federal income tax; a Roth contribution costs the full amount now.

At this income every traditional dollar costs 88 cents of take-home pay, because the saving comes from the 12% federal bracket. In the 22% bracket the cost drops to 78 cents, which is why traditional contributions are most valuable for higher earners.

Increasing your rate without feeling it

The easiest time to raise a 401(k) contribution is when your pay goes up. Raising your rate by half of each raise means your paycheck still grows while your savings rate climbs. Many plans offer automatic annual increases of 1% until you reach a cap you choose. Starting at 6% and increasing by 1% a year reaches 15% in nine years, without any single year's paycheck shrinking. Pair increases with the start of a new year or open enrollment, when you review other deductions anyway.

Loans and hardship withdrawals

Most plans let you borrow from your 401(k), generally up to half your vested balance or $50,000, whichever is less, repaid through payroll over up to five years. Repayments come from after-tax pay, so a loan lowers take-home pay without lowering taxable income. If you leave your job, any unpaid balance may be treated as a distribution unless you repay it by your tax filing deadline. Hardship withdrawals are taxed and, before age 59 1/2, usually face a 10% penalty, so treat both as a last resort.

How the match changes the math

An employer match makes the true return on your first contributions very high. With a 50% match on the first 6% of pay, a $65,000 earner who contributes $3,900 gets $1,950 from the employer. The traditional contribution costs about $3,432 of take-home pay, so every dollar of take-home given up becomes about $1.70 in the account immediately. No other common investment comes close, which is why the first priority is always to contribute enough to get the full match, even when money is tight.

Check your plan and payroll assumptions

Traditional employee deferrals generally reduce current federal taxable income, but remain subject to Social Security and Medicare. See the IRS 401(k) participant guide.

This estimate assumes 26 paychecks, a simple employer match and a flat state tax input. It does not cap contributions at your legal limit or model vesting. Confirm those details with your plan administrator. For a bonus contribution, use the bonus take-home calculator alongside your plan rules; for federal withholding settings, use the W-4 calculator.