How it works
Use comparable purchase quotes and the same years and distance for both cars. Each vehicle's economic cost combines depreciation, fees, interest and running costs. Purchase principal is included through purchase price minus resale, so do not enter full loan payments as interest. Enter financing interest incurred within the selected ownership period, even if the loan term is longer.
Choose the correct energy boundary for the EV consumption figure. Wall or grid consumption already includes charging losses and needs no additional efficiency adjustment. Battery-only consumption is divided by charging efficiency to estimate wall electricity. Use a blended price when charging at several locations, and include fixed subscriptions or recurring fees in the EV's annual non-energy budget.
The formula behind the estimate
Every result starts with a defined model and visible assumptions.
Annual gasoline cost = annual miles ÷ US mpg × price per US gallon Metric gasoline cost = annual km × L/100 km ÷ 100 × price per liter Annual EV wall kWh = annual distance × kWh per 100 distance ÷ 100 For battery-only consumption, divide energy by charging efficiency Vehicle total = purchase price − resale + upfront fees + charger (EV only) + period interest + years × (annual energy + annual other costs) EV cost advantage = gasoline total − EV total
A worked example
At 12,000 miles per year, 30 US mpg and $3.50 per gallon, gasoline costs $1,400 annually. An EV using 30 wall kWh per 100 miles at $0.20 per kWh costs $720 annually. With the default five-year purchase, resale, fee, interest and other-cost assumptions, gas ownership totals $36,800 and EV ownership totals $35,700. The EV costs $1,100 less in this illustrative scenario; different quotes and resale values can reverse the result.
Energy savings are only one cost component
The annual energy row compares fuel and electricity spending alone. The primary result also includes purchase value loss, fees, charging equipment, interest and other running costs. Lower energy spending does not by itself establish which vehicle costs less over the selected period.
Resale and annual running costs are user assumptions rather than make-specific predictions. The model does not claim that every electric car has lower insurance or maintenance costs. Obtain quotes for the actual vehicles and test both optimistic and cautious assumptions.
Keep the charging inputs consistent
A wall-energy rating and a battery dashboard reading measure different boundaries. Adding a second loss factor to an input that already includes charging losses overstates electricity use. Choose battery mode only when the consumption source measures energy from the battery.
The electricity price is per wall kWh. Time-based charging, idle fees, parking charges, subscriptions and demand charges need a suitable effective unit price or separate annual costs. This model is for gasoline versus a battery-electric vehicle; plug-in hybrid fuel splits require a different calculation.
Questions worth asking
Is an electric car cheaper than a gas car?
It depends on purchase price, resale, energy rates, driving distance, insurance, maintenance and financing. Enter matched local scenarios to compare the full ownership totals.
Are charging losses included twice?
Wall-energy mode applies no extra loss. Battery-energy mode divides consumption by your entered charging efficiency once.
Are incentives and electricity prices updated?
No. Use your own verified purchase price and energy rates. No current incentive, tax eligibility or local tariff is inferred.
Should I include the entire loan payment?
No. Depreciation accounts for purchase principal. Enter only interest incurred during the comparison period, with fees counted once.
Can I compare in kilometers and local currency?
Yes. The unit switch converts distance, fuel economy, fuel price and EV consumption together. Eight currencies are available for display; monetary values are not exchanged.
This is general information, not personalized financial advice. Read the limitations.
