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EV & CarsGenerated accuracy model review: 2026-05-06
EV Charging Cost vs Gas 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
- EV cost = miles / mi per kWh / (1 - loss) * electricity price. Gas cost = miles / MPG * gas price.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Miles Driven: 1,000 mi
- EV Efficiency Preset: tesla_model_y_long_range
- EV Efficiency: 3.5 mi/kWh
- Electricity Rate Preset: eia_us_residential_average
- Electricity Price: 0.16 $/kWh
- Gas MPG Preset: epa_2026_honda_crv_fwd
- Gas Vehicle MPG: 28 MPG
- Fuel Price Preset: eia_us_regular_gasoline_2026_05_04
- Gas Price: 3.8 $/gal
- Charging Loss: 10%
Expected outputs
- Lower Cost Option: EV charging is lower
- EV Charging Cost: $48.19
- Gas Cost: $148.40
- Estimated Savings: $100.21
- EV Cost per Mile: $0.05
- Gas Cost per Mile: $0.15
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 and vehicle assumptions are user-entered.
- Charging loss is modeled as a simple percentage.
- Calculations run locally in your browser and are not stored by Calwarden.
- Results are planning estimates, not financial, tax, insurance, legal, or mechanical advice.
Unit handling
- Miles Driven accepts values in mi.
- EV Efficiency Preset accepts one of the configured options.
- EV Efficiency accepts values in mi/kWh.
- Electricity Rate Preset accepts one of the configured options.
- Electricity Price accepts values in $/kWh.
- Gas MPG Preset accepts one of the configured options.
- Gas Vehicle MPG accepts values in MPG.
- Fuel Price Preset accepts one of the configured options.
- Gas Price accepts values in $/gal.
- Charging Loss accepts values in %.
- EV Charging Cost is displayed as currency.
- Gas Cost is displayed as currency.
- Estimated Savings is displayed as currency.
- EV Cost per Mile is displayed as currency.
- Gas 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 ev-charging-cost-vs-gas-cost-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for EV Charging Cost vs Gas Cost Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.