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EV & CarsGenerated accuracy model review: 2026-05-06
Hybrid vs Gas Savings 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 savings = gas annual fuel cost - hybrid annual fuel cost. Payback = premium / annual savings.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Annual Miles: 12,000 mi/yr
- Gas MPG Preset: epa_2026_honda_crv_fwd
- Gas Vehicle MPG: 30 MPG
- Hybrid MPG Preset: epa_2026_toyota_camry_hybrid_le
- Hybrid MPG: 48 MPG
- Fuel Price Preset: eia_us_regular_gasoline_2026_05_04
- Fuel Price: 3.8 $/gal
- Hybrid Price Premium: $2,500
Expected outputs
- Annual Fuel Savings: $733.27
- Gas Annual Fuel Cost: $1,780.80
- Hybrid Annual Fuel Cost: $1,047.53
- Fuel Payback: 3.41 years
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.
- Gas MPG Preset accepts one of the configured options.
- Gas Vehicle MPG accepts values in MPG.
- Hybrid MPG Preset accepts one of the configured options.
- Hybrid MPG accepts values in MPG.
- Fuel Price Preset accepts one of the configured options.
- Fuel Price accepts values in $/gal.
- Hybrid Price Premium accepts values in $.
- Annual Fuel Savings is displayed as currency.
- Gas Annual Fuel Cost is displayed as currency.
- Hybrid Annual Fuel Cost is displayed as currency.
- Fuel Payback is displayed in years.
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 hybrid-vs-gas-savings-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for Hybrid vs Gas Savings Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.