Should you pay tax now (Roth) or later (Traditional)? Enter your yearly contribution, your tax rate today and the one you expect in retirement, a return and the number of years. The calculator compares the after-tax value of each account, tells you which comes out ahead and by how much, and shows the break-even retirement tax rate.
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Same take-home cost: the Roth gets the contribution minus today's tax. Same contribution: you put the same amount in each, and the Traditional tax savings are invested in a taxable account.
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Enter your own amount within the current IRS limit.
years
%
Federal + state rate on your last dollar of income.
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Average rate on withdrawals in retirement.
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%
Enter your values to see the result.
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How to use the Traditional vs Roth IRA Calculator
Choose the comparison: same take-home cost (classic) or the same contribution in both accounts.
Enter your yearly contribution and the years until retirement.
Enter your current marginal tax rate and the rate you expect on withdrawals in retirement.
Set the expected return (and the tax on taxable gains if you compare equal contributions).
Read which account wins, by how much, and the break-even retirement tax rate.
How the comparison works
Contributions are made at the start of each year and grow at the same return in both accounts:
FV = C × ((1 + i)n − 1) ÷ i × (1 + i)
Traditional after tax = FV(C) × (1 − retirement tax rate)
Roth (same contribution) = FV(C); the Traditional side adds FV(C × current tax rate) in a taxable account, minus tax on its gains
Example (same take-home cost): $7,000 a year for 30 years at 7% grows to $707,511. Traditional at a 15% retirement rate keeps $601,385. The Roth gets $7,000 × (1 − 22%) = $5,460 a year and grows to $551,859 tax-free, so Traditional wins by $49,526. Swap the rates (15% now, 22% later) and the Roth wins.
Rules of thumb
Your situation
Usually better
Why
Low income now, expect higher income later
Roth
Pay tax at today's low rate
Peak earning years, high bracket
Traditional
Deduct at a high rate, withdraw at a lower one
Same tax rate now and later
Tie (Roth if you can max out)
Same math; Roth shelters more when contributions are capped
It mostly depends on your tax rate now versus in retirement. If you expect a lower rate in retirement, Traditional (deduct now, pay tax later) usually wins; if you expect a higher rate, Roth (pay tax now, withdraw tax-free) usually wins. With the same rate and the same take-home cost, they end up equal.
Why are they equal when tax rates are the same?
Multiplication is commutative. A Traditional account grows C × growth and is then taxed: C × growth × (1 − t). A Roth starts with C × (1 − t) and grows: C × (1 − t) × growth. The results are identical when the tax rate t is the same at both ends.
What is the 'same contribution' comparison?
If you can afford to put the same dollar amount into either account, the Roth effectively shelters more money because its contributions are after tax. To compare fairly, this mode invests the Traditional account's yearly tax savings in a regular taxable account and taxes its gains at the rate you enter. In this case the Roth often wins even at equal tax rates.
What tax rate should I use for retirement?
Use your expected effective (average) tax rate on withdrawals, which is often lower than your current marginal rate because withdrawals fill the lower brackets first. Consider other income in retirement such as Social Security, pensions and required minimum distributions, and that tax laws can change.
Does this include contribution or income limits?
No. Enter an amount you are allowed to contribute. IRA contribution limits change most years, Roth IRA eligibility phases out at higher incomes, and Traditional IRA deductions can be limited if you have a workplace plan. Check the current IRS rules.
Can I use this for a Roth 401(k) vs a pre-tax 401(k)?
Yes. The tax math is the same: pre-tax contributions are taxed on withdrawal and Roth contributions are taxed now. Just enter your 401(k) contribution and tax rates.
Are there other reasons to choose a Roth?
Roth IRAs have no required minimum distributions for the original owner, contributions (not earnings) can be withdrawn without tax or penalty, and having both pre-tax and Roth money gives you flexibility to manage your tax bracket in retirement. Many people split contributions between the two.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.