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Finance & LoansGenerated accuracy model review: 2026-05-06

Roth IRA accuracy and testing

This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.

Formula source

  • The calculator projects future value using compound interest. It then calculates the 'Tax Saved' by comparing the tax-free Roth total against a taxable account where gains would be taxed upon withdrawal.

Test cases

Default input regression check

Generated from the checked-in default inputs and calculate function.

Inputs

  • IRA Limit Preset: irs_retirement_limits_2026
  • Current Balance: $10,000
  • Annual Contribution: $7,500
  • Manual IRA Limit: $7,500
  • Years to Grow: 25
  • Annual Return: 7%
  • Tax Rate in Retirement: 25%

Expected outputs

  • Total Roth Value: $528,642.11
  • Taxable Equivalent: $396,481.58
  • Est. Tax Saved: $132,160.53

Known limitations

  • Assumes tax rate stays constant for the comparison. Does not enforce income eligibility limits for contributions.

Assumptions

  • Inputs are interpreted exactly as entered in the calculator form.
  • The calculation runs locally in the browser using the current checked-in calculator definition.

Unit handling

  • IRA Limit Preset accepts one of the configured options.
  • Current Balance accepts values in $.
  • Annual Contribution accepts values in $.
  • Manual IRA Limit accepts values in $.
  • Years to Grow accepts numeric values.
  • Annual Return accepts values in %.
  • Tax Rate in Retirement accepts values in %.
  • Total Roth Value is displayed as currency.
  • Taxable Equivalent is displayed as currency.
  • Est. Tax Saved is displayed as currency.

Rounding rules

  • Number displays use up to 2 decimal places in the calculator UI.
  • Currency outputs are displayed with standard US dollar formatting.

Version history

1.0.0 - 2026-05-06

Generated accuracy and testing page from the current roth-ira-calculator calculator definition.

Change log

2026-05-06

Published default regression test documentation and metadata fallbacks for Roth IRA.

Calculator transparency

Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.

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