Confidence Interval Calculator
Intervals for a mean or a proportion, with the margin of error.
IRA Calculator
Traditional against Roth, compared on an after-tax basis.
A traditional contribution costs less out of pocket because it is deductible. Without investing that difference, the comparison silently favours Roth and gives the wrong answer.
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Traditional, after tax
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Roth, after tax
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Nothing further is owed on withdrawal.
| Year | Balance | Traditional after tax | Roth after tax |
|---|
Better choice
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Account balance—
Total contributed—
Growth earned—
Annual tax deduction—
Side account value—
Tax due on traditional—
Quick Tool Overview
The IRA Calculator runs traditional and Roth side by side and reports what you would actually keep after tax. Crucially it can reinvest the traditional deduction, without which the comparison silently favours Roth and gives the wrong answer.
- What it does
- Compares traditional and Roth IRAs on an after-tax basis
- You give it
- Contributions, years, return and your tax rates now and later
- You get back
- Both balances after tax, and which comes out ahead
- Best for
- Making the traditional versus Roth decision properly
About the IRA Calculator
Enter your contribution, the years until retirement and the return you expect to project an IRA forward. The calculator runs both account types side by side and reports the after-tax result, which is the only basis on which they can be fairly compared.
The comparison has a subtlety most simple calculators miss. A traditional IRA contribution is deductible, so contributing the same nominal amount to each account costs you less out of pocket with a traditional. Doing the comparison properly means investing that tax saving alongside, otherwise the traditional side is understated. This calculator has an option to do exactly that, and with equal tax rates now and later the two accounts then produce identical results, which is the correct and often surprising answer.
Key features of the IRA Calculator
The deduction reinvested
A traditional contribution costs less out of pocket, and investing that difference is what makes the comparison honest.
Equal-rate case shown
With the same tax rate now and later the two are mathematically identical — a surprising result most calculators hide.
After-tax balances
The traditional figure net of withdrawal tax, so you are comparing money you can spend.
Split contribution modelling
Hedge the tax-rate uncertainty by contributing to both, and see the blended result.
Year-by-year growth
The full accumulation path rather than just the endpoint.
How to use the IRA Calculator
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1
Enter your contribution
The annual amount and the number of years you will keep contributing.
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2
Set the expected return
The average annual return, and the years until you begin withdrawing.
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3
Enter your tax rates
Your marginal rate now and your expected rate in retirement.
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4
Reinvest the deduction
Enable this for a like-for-like comparison rather than one that favours Roth by default.
Frequently asked questions
A traditional IRA gives a deduction now and taxes withdrawals later. A Roth gives no deduction but withdrawals are tax free. Contribution limits are shared between them, and both grow without annual tax on gains.
Roth if you expect a higher tax rate in retirement than today, traditional if you expect a lower one. When you genuinely cannot tell, splitting between both hedges the uncertainty and gives flexibility later.
Because a traditional contribution costs less out of pocket. Comparing equal contributions without investing that difference understates the traditional account. With equal tax rates and the deduction invested, the two are mathematically identical.
Generally from 59 and a half without penalty. Earlier withdrawals usually incur a ten percent penalty plus tax, with some exceptions. Traditional IRAs also require minimum distributions from your seventies; Roth IRAs do not.
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