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

Retirement Calculator 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 applies compound interest to your initial balance and uses the Future Value of an Annuity formula for your monthly contributions over the number of years until retirement.

Test cases

Default input regression check

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

Inputs

  • Current Age: 30
  • Retirement Age: 65
  • Current Savings: $50,000
  • Monthly Contribution: $500
  • Annual Return: 7%

Expected outputs

  • Total at Retirement: $1,475,834.89
  • Total Interest Earned: $1,215,834.89
  • Years to Grow: 35

Known limitations

  • Assumes a constant rate of return every year, which does not reflect actual market volatility. Does not account for taxes or inflation explicitly.

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

  • Current Age accepts numeric values.
  • Retirement Age accepts numeric values.
  • Current Savings accepts values in $.
  • Monthly Contribution accepts values in $.
  • Annual Return accepts values in %.
  • Total at Retirement is displayed as currency.
  • Total Interest Earned 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 retirement-calculator calculator definition.

Change log

2026-05-06

Published default regression test documentation and metadata fallbacks for Retirement Calculator.

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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