Cernarus

Roth IRA Calculator

This tool helps you model three Roth IRA scenarios: projecting a Roth balance from ongoing contributions, estimating taxes and outcomes for a Roth conversion, and comparing Roth versus Traditional IRA outcomes after taxes. Use realistic inputs and understand outputs are projections based on assumptions you provide.

Projections assume constant nominal returns and stable contribution patterns unless you change inputs. The calculator includes protections for zero-return cases and clearly shows intermediate values (years, tax due, after-tax amounts) to support decision-making.

Updated Nov 21, 2025

Estimate your Roth IRA balance at retirement given current balance, ongoing annual contributions, expected return, and contribution timing.

Inputs

Results

Updates as you type

Estimated Roth IRA balance at retirement

$589,218.94

Future value of contributions

$474,349.12

Years until retirement

30

OutputValueUnit
Estimated Roth IRA balance at retirement$589,218.94USD
Future value of contributions$474,349.12USD
Years until retirement30years
Primary result$589,218.94

Visualization

Methodology

All growth calculations use standard discrete annual compounding and annuity future-value formulas. For contributions we use a future-value annuity formula; the tool adjusts the annuity factor when the return is zero to avoid division-by-zero errors.

Conversion tax estimates multiply the conversion amount by the provided tax rate; the net converted amount is then projected forward using the same compounding assumptions as contributions. Comparison mode computes post-tax Roth contributions today and compares their projected value to a Traditional IRA balance after applying the retirement tax rate to withdrawals.

Key takeaways

Use projection mode to estimate how regular Roth contributions grow under your return assumption.

Use conversion mode to estimate tax due now and the projected Roth value of the converted funds.

Use compare mode to see an apples-to-apples comparison of identical gross contributions to Roth (post-tax) vs Traditional (pre-tax) accounts, presented as after-tax retirement balances.

Further resources

Expert Q&A

Does this calculator include contribution limits or eligibility rules?

No. This calculator focuses on growth and tax effects. Contribution limits, income phaseouts, and eligibility rules are governed by tax law. See the IRS citation below for current-year contribution limits and eligibility.

Are results guaranteed?

No. Results are estimates based on inputs and mathematical models. Actual returns, taxes, and future tax rates can differ. Use this tool for planning, not as definitive tax or investment advice.

How does contribution timing affect results?

Contributions made at the start of each period compound for an extra period compared with end-of-period contributions. The calculator models both options using the annuity future-value factor.

Does the tool model taxes on investment returns inside Traditional IRAs?

The tool assumes Traditional IRA growth is pre-tax and entire withdrawals are taxed at the retirement tax rate you provide. It does not model partial conversions, required minimum distributions, or state taxes.

What assumptions does the conversion estimator make about tax payment?

The conversion estimator assumes taxes on the conversion are paid from funds outside the converted amount unless you enter a conversion_amount that includes the tax. Confirm your funding source with a tax advisor.

Sources & citations