Same contribution, different tax now vs later. See which leaves more after tax.
Ad
Same paycheck hit is the useful comparison. Traditional uses pre-tax $X, so more reaches the account. Roth uses after-tax dollars, so Roth invests $X × (1 − current tax rate) to cost the same on your paycheck. Comparison A (same dollars into the account) is shown too — it is not apples-to-apples. Educational estimate, not tax advice.
The link updates with your numbers so you can share this comparison. 2026 IRS limits are shown as a check, not a hard cap.
Verdict
—
B · Recommended
Same paycheck cost
Traditional invests the pre-tax amount. Roth invests that amount × (1 − current tax rate). Both cost the same take-home dollars.
Paycheck cost / year
—
Extra Traditional invested / year
—
Traditional after tax at retirement
—
Roth tax-free at retirement
—
Traditional
Roth
Into the account / year
—
—
Account value (pre-tax)
—
—
A · Not apples-to-apples
Same contribution dollars into the account
Both accounts receive the pre-tax equivalent. Roth still pays tax on those dollars now, so your paycheck shrinks more than Traditional.
Traditional paycheck cost / year
—
Roth paycheck cost / year
—
Traditional after tax at retirement
—
Roth tax-free at retirement
—
Current balance (optional)
Modeled as already in that account type. Converting Traditional to Roth is a taxable event and is not included.
If already Traditional, after tax
—
If already Roth, tax-free
—
Ad
2026 limits: 401(k)/403(b)/457/TSP employee deferral $24,500; catch-up age 50+ $8,000 (total $32,500); super catch-up ages 60–63 $11,250 (total $35,750) if the plan allows; combined employee+employer 401(k) $72,000 plus catch-up as applicable. IRA (Traditional or Roth) $7,500; catch-up 50+ $1,100 (total $8,600). Employer match is not modeled.
FAQ
Should I compare Roth vs Traditional with the same contribution or the same paycheck cost?
Same paycheck cost is the useful comparison. Traditional uses pre-tax dollars, so more money reaches the account for the same hit to take-home pay. Roth uses after-tax dollars, so the account gets less up front. Putting the same dollar amount into each account is not apples-to-apples, because Roth shrinks your paycheck more.
When is a Roth 401(k) or Roth IRA better than Traditional?
On a same-paycheck comparison, Roth usually leaves more after tax if you expect a higher tax rate in retirement. Traditional usually leaves more if you expect a lower rate later. If the rates are similar, it is a toss-up, and Traditional still invests extra principal up front because of the deduction. This is an educational estimate, not tax advice.
Do high earners have to make 401(k) catch-up contributions as Roth in 2026?
SECURE 2.0 may require some catch-up contributions at work to be Roth. For 2026, high earners (prior-year FICA wages from that employer at or above the IRS catch-up Roth threshold, commonly reported as $150,000) may be required to make 401(k) catch-ups as Roth; confirm with your plan. This calculator does not switch catch-ups to Roth automatically.
Educational estimate only. Not tax, investment, or legal advice. Future returns, tax law, and your situation will differ. 2026 IRS figures are labeled as 2026 limits.
