Roth vs. Traditional Calculator

How the Roth vs. Traditional Calculator works

This tool projects the after-tax value of the same retirement contribution made either way — Traditional (pre-tax now, taxed at withdrawal) or Roth (taxed now, tax-free at withdrawal) — using your expected tax rate today and in retirement, and the 2026 contribution limits for your account type.

The formula

Both formulas compound the same way — the only difference is whether the tax haircut is applied before growth (Roth) or after growth (Traditional). When the two tax rates are identical, both formulas produce the same number.

Common mistakes

• Comparing the same nominal contribution amount for both — a Roth contribution costs more out of pocket today than a Traditional one for the same pre-tax dollar figure.
• Assuming your retirement tax bracket will match your current one — Social Security, RMDs, and pension income can push it higher or lower than expected.
• Ignoring state income tax — this calculator only models federal rates; a state with no income tax favors Traditional less than one with a high rate.

Frequently asked questions

What actually moves this number

Specific levers, and roughly what each one is worth. Not “save more” — the things that change the figure above by an amount you can measure.

• Split rather than agonize

  Nobody knows their future bracket. Contributing to both gives you tax-free and taxable buckets to draw from in retirement, which lets you manage the year's taxable income deliberately — often worth more than getting the original call right.

• Favor Roth in an unusually low-income year

  A gap year, a sabbatical, a first job, or early retirement before benefits start are the moments when paying tax now is cheapest. The same logic makes those years the best ones for Roth conversions.

• Remember Roth removes the RMD problem

  Traditional balances force taxable withdrawals in your seventies on the IRS schedule whether you need the money or not. Roth IRAs have no lifetime RMD, and Roth 401(k)s no longer do either.

• Factor in the state you expect to retire in

  Contributing traditional in a high-income-tax state and withdrawing in a no-income-tax one captures a deduction you never repay. Moving the other direction does the reverse, and it is a swing large enough to flip the answer.

What this calculator does not cover

Every calculator simplifies, and the useful thing is knowing exactly where. These are the specific gaps between this estimate and your real situation:

• The comparison turns on your tax rate now versus in retirement, which nobody knows. Treat the result as a sensitivity test rather than an answer.
• It does not model required minimum distributions, which apply to traditional balances and not to Roth IRAs during the owner's lifetime.
• Income phase-outs for Roth IRA eligibility and traditional IRA deductibility are not modeled.
• State tax now versus state tax in retirement can flip the answer, particularly if you expect to move between a high-tax and a no-income-tax state.

For anything that turns on an exact figure, use the primary sources below or a qualified professional. How these limits are decided and disclosed is described in the editorial standards.