Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Roth balance (tax-free)
$752,573
Total contributed
$222,000
Investment growth
$530,573
Same money in a taxable account
$672,987
Roth tax advantage
$79,586
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How to use this
- 1Enter current balance ($).
- 2Enter annual contribution ($).
- 3Enter years to grow.
- 4Enter annual return (%).
- 5Enter capital gains rate (%).
- 6Read your roth balance (tax-free) on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Roth contributions are made with after-tax money, but the growth and the withdrawals are tax-free. The advantage compounds — the longer the runway, the bigger the gap versus a taxable brokerage account.
Worked example
Using the values the calculator loads with:
Inputs
- Current balance: 12000 $
- Annual contribution: 7000 $
- Years to grow: 30
- Annual return: 7 %
- Capital gains rate: 15 %
Results
- Roth balance (tax-free): $752,572.56
- Total contributed: $222,000.00
- Investment growth: $530,572.56
- Same money in a taxable account: $672,986.68
- Roth tax advantage: $79,585.88
What each field means
Inputs
- Current balance ($)
- The current balance used in the calculation, measured in $. Starts at 12000 $ so you have a working example on load.
- Annual contribution ($)
- The annual contribution used in the calculation, measured in $. Starts at 7000 $ so you have a working example on load.
- Years to grow
- The years to grow used in the calculation. Starts at 30 so you have a working example on load.
- Annual return (%)
- The annual return used in the calculation, measured in %. Starts at 7 % so you have a working example on load.
- Capital gains rate (%)
- The capital gains rate used in the calculation, measured in %. Starts at 15 % so you have a working example on load. Accepted range: 0–45 %.
Results
- Roth balance (tax-free)
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total contributed
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Investment growth
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Same money in a taxable account
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Roth tax advantage
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the roth ira calculator work?
Roth contributions are made with after-tax money, but the growth and the withdrawals are tax-free. The advantage compounds — the longer the runway, the bigger the gap versus a taxable brokerage account. The underlying maths is: Both accounts compound identically; the taxable comparison deducts capital gains tax on growth at the end.
What do I need to enter?
5 values: current balance, annual contribution, years to grow, annual return, and capital gains rate. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the roth balance (tax-free) result mean?
It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Roth IRA Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/roth-ira
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/roth-ira" target="_blank" rel="noopener">Roth IRA Calculator — RevenueLab</a> (2026).</p>
Source: [Roth IRA Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/roth-ira) (2026).