Roth vs Traditional IRA Calculator
Pay tax now or later? Compare the after-tax value of both IRAs at your tax rates and see which one wins.
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Winner (after-tax value)
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Compared on equal pre-tax dollars, so the tax timing is the only difference.
How it works
Both accounts grow by the same annuity factor over n years:
To keep the comparison fair, the calculator starts both with the same pre-tax dollars. Roth contributions are after-tax, so less actually gets invested; Traditional contributions go in pre-tax and are taxed on withdrawal:
When today's and retirement tax rates are equal, the two formulas are mathematically identical — neither account has an edge. The winner is decided entirely by which tax rate is lower.
Frequently asked questions
When is a Roth IRA better than a Traditional IRA?
Generally when your tax rate in retirement will be equal to or higher than your tax rate today. You pay tax now at today's rate, and qualified withdrawals later are tax-free.
When does a Traditional IRA win?
When your retirement tax rate will be lower than today's — the common case for high earners who expect less income in retirement. You get the deduction now and pay the lower rate later.
What if tax rates are the same now and in retirement?
Then the two accounts give identical after-tax results for the same pre-tax contribution. The math is symmetric: (1 − tax) × growth equals growth × (1 − tax).
Are there income limits for these accounts?
Yes. Roth IRA contributions phase out above certain incomes, and Traditional IRA deductions can be limited if you or your spouse has a workplace retirement plan. This calculator ignores limits and focuses on the tax math.