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Traditional vs Roth calculator

Should you pay tax now or later? Compare the after-tax money a traditional and a Roth account leave you with, using your tax rate today and in retirement.

By the Calcist team · Checked against known answers · Updated October 27, 2026

Data: 2026 contribution limits, your own tax rates · Source: IRS Notice 2025-67, IRS Publication 590-A · Last reviewed October 2026

Private: calculated on your device. Nothing you type is sent anywhere.

Estimates for planning, not financial, tax or legal advice. Figures use US rules unless the page says otherwise.

Next: Already have a big traditional balance? See whether moving it pays with the Roth conversion calculator.

How the comparison works

This compares US traditional and Roth accounts under federal tax rules. Both accounts start from the same pre-tax budget. With a traditional account the whole amount goes in and is taxed when you withdraw it. With a Roth, tax comes off first and the rest grows tax-free.

Traditional after tax = budget × growth × (1 − retirement tax rate)
Roth = budget × (1 − tax rate now) × growth
growth = (1 + r) + (1 + r)² + … + (1 + r)ⁿ for yearly contributions

Equal tax rates give equal results

Multiplication doesn't care about order. Taking 22% off before growth or after growth leaves the same amount. So the only thing that decides the winner is whether your tax rate is higher now or later. The break-even retirement tax rate is simply your tax rate now.

Worked example

$10,000 a year for 30 years at 7%: the traditional account grows to $1,010,730. At a 12% retirement rate you keep $889,443. The Roth gets $7,800 a year after 22% tax, growing to $788,370, all tax-free. Traditional wins by $101,073 because 12% later is less than 22% now. If you expected 30% later, Roth would win.

What this leaves out

  • Contribution limits. The limit is the same dollar amount for both. If you max out, a Roth holds more after-tax money: $24,500 in a Roth 401(k) is worth more than $24,500 in a traditional one. To compare fairly at the limit, the traditional saver would also need to invest the tax savings.
  • Your actual rates. Use your marginal rate now (the rate on the money you'd contribute) and the average rate you expect on withdrawals. Retirement withdrawals often fill lower brackets first.
  • Other rules. Roth IRAs have no required minimum distributions, and traditional withdrawals can raise taxes on Social Security and Medicare premiums. Roth withdrawals of earnings need the account to be 5 years old and you to be 59½.
  • Matching contributions from an employer go in pre-tax either way and aren't included.

Sources

How we checked this

Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:

  • $10,000 a year, 22% now, 12% later, 30 years at 7%: traditional by $101,073 ✓
  • 1 year, 0% return, 24% now, 32% later: Roth by $800 ✓
  • Edge: equal 25% rates: same either way ($130,197) ✓

Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.

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Questions people ask

Is Roth or traditional better?

Roth is better if your tax rate when you withdraw will be higher than it is now. Traditional is better if it will be lower. If the rates are the same, both leave you with exactly the same amount.

Why do equal tax rates give the same result?

Because the tax is a multiplication. 22% off before 30 years of growth, or 22% off after, leaves the same number of dollars.

What tax rate should I use for retirement?

Estimate the rate on your withdrawals: your expected income in retirement, including Social Security and pensions, run through the brackets. Many people drop to a lower bracket, but large balances and required withdrawals can keep it high.

Can I split between traditional and Roth?

Yes. Many 401(k) plans let you split contributions, and the yearly limit applies to the total. Splitting hedges your bet on future tax rates.

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