Conversions
Distance uses 1 mile = 1.609344 kilometres. A US liquid gallon is 3.785411784 litres; an Imperial gallon is 4.54609 litres. Pressure uses 1 PSI = 0.0689476 bar. Mechanical horsepower and metric PS are kept distinct.
Fuel and energy
Economy divides distance by fuel; consumption divides fuel by distance and commonly scales to 100 km. EV cost accounts for entered charging efficiency by dividing battery energy by that efficiency before multiplying by the electricity rate.
Finance and geometry
Loan payments use the standard amortising-payment relationship with a monthly rate. Tyre diameter adds two sidewalls to rim diameter after converting inches to millimetres. All calculators retain precision internally and round for display.
Reference sources
- NIST Guide to the SI for measurement conventions and conversions.
- FuelEconomy.gov for the context affecting real fuel use.
- NHTSA tyre guidance for pressure labels and tyre safety.
- U.S. Department of Energy charging guidance for charger and vehicle limits.
- CFPB auto-loan resources for evaluating loan terms and costs.
Worked examples are illustrative calculations using stated inputs, not quotations, vehicle tests or current market prices.
Uncertainty
Outputs based on future prices, road conditions, depreciation, charging power or maintenance are scenarios rather than promises. We encourage high and low cases and verification against official specifications.
Last updated: September 10, 2026