Roth vs. Traditional 401(k) and Your Paycheck

See how much more of each paycheck a Roth 401(k) contribution takes than a pre-tax one of the same size, and whether your catch-up must go in as Roth in 2026. Pair this with the roth ira calculator for a fuller picture before you make a decision.

Enter your pay and contribution

2026 tax rules and 401(k) limits

Annual gross salary

Pay frequency

Filing status

401(k) contribution

The same share of pay goes in as Roth or as pre-tax.

State and local income tax rate

Use 0 for none.

Your age at the end of 2026

Catch-up contributions start at 50.

Catch-up contribution

$/ year

On top of the regular limit, age 50+.

2025 Social Security wages from this employer

W-2 box 3. Over $150,000 means catch-ups must be Roth.

More options

Health premiums and other pre-tax deductions

$/ check

Health, dental and vision premiums, HSA or FSA.

Children under 17

Other dependents

Roth vs traditional on each paycheck

Extra a Roth costs per paycheck

–

Take-home with traditional

–

Take-home with Roth

–

Extra a Roth costs per year–

Contribution per paycheck–

Tax rates on the traditional deferral–

Roth contribution with the same take-home as traditional–

Roth catch-up rule applies–

Paycheck side by side

Per paycheck, for the same contribution. The difference column is the Roth paycheck minus the traditional paycheck.

Item	Traditional	Roth	Difference

The Roth premium at other contribution rates

How much more of each paycheck a Roth contribution takes than a pre-tax one, at rates from 2% to 20% of pay. That extra is income tax paid now instead of in retirement.

Contribution rate	Contribution per paycheck	Take-home, traditional	Take-home, Roth	Roth costs extra per paycheck	Per year

Results are estimates for educational purposes and are not financial, tax or legal advice.