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Everyday LifeGenerated accuracy model review: 2026-05-06
Fuel 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
- **Gallons Needed = Distance / MPG** **Total Cost = Gallons Needed × Price per Gallon**
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Trip Distance: 100 miles
- Vehicle MPG Preset: epa_2026_honda_civic_4dr
- Fuel Efficiency: 25 MPG
- Fuel Price Preset: eia_us_regular_gasoline_2026_05_04
- Gas Price: 3.5 $/gal
Expected outputs
- Total Cost: $13.09
- Fuel Needed: 2.94 gallons
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
- MPG is treated as an average for the trip, not a live reading.
- Gas price is constant across the whole journey.
- Distance is entered in miles and should include a round trip if needed.
Unit handling
- Trip Distance accepts values in miles.
- Vehicle MPG Preset accepts one of the configured options.
- Fuel Efficiency accepts values in MPG.
- Fuel Price Preset accepts one of the configured options.
- Gas Price accepts values in $/gal.
- Total Cost is displayed as currency.
- Fuel Needed is displayed in gallons.
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 fuel-cost-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for Fuel Cost Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.