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EV & CarsGenerated accuracy model review: 2026-05-06

Car Maintenance Cost 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

  • Annual maintenance = routine service + tire reserve + repair reserve + other. Monthly cost = annual / 12.

Test cases

Default input regression check

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

Inputs

  • Annual Miles: 12,000 mi/yr
  • Routine Service: 650 $/yr
  • Tire Reserve: 400 $/yr
  • Repair Reserve: 900 $/yr
  • Other Maintenance: 0 $/yr

Expected outputs

  • Monthly Maintenance Budget: $162.50
  • Annual Maintenance Cost: $1,950.00
  • Maintenance Cost per Mile: $0.16

Known limitations

  • This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
  • Use the result as a planning estimate unless the calculator page states a stricter purpose.

Assumptions

  • All prices, fees, rates, and vehicle assumptions are user-entered.
  • Calculations run locally in your browser and are not stored by Calwarden.
  • This is planning math, not financial, tax, insurance, legal, or mechanical advice.

Unit handling

  • Annual Miles accepts values in mi/yr.
  • Routine Service accepts values in $/yr.
  • Tire Reserve accepts values in $/yr.
  • Repair Reserve accepts values in $/yr.
  • Other Maintenance accepts values in $/yr.
  • Monthly Maintenance Budget is displayed as currency.
  • Annual Maintenance Cost is displayed as currency.
  • Maintenance Cost per Mile 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.
  • Input precision follows configured step values where provided.

Version history

1.0.0 - 2026-05-06

Generated accuracy and testing page from the current car-maintenance-cost-calculator calculator definition.

Change log

2026-05-06

Published default regression test documentation and metadata fallbacks for Car Maintenance Cost 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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