Electric vs Gas Car Cost Calculator
What an electric car saves on fuel each year, and when it pays back its higher price.
Good to know. Fast chargers on the motorway cost two to three times home power. Where you charge matters most.
Approximate. Real-world values vary.
How it works
In plain words
Each car’s cost per km is its energy use times the energy price: litres per km times the fuel price, and kWh per km times the electricity price. Multiply by the distance you drive in a year. The payback time is the extra price of the electric car divided by what it saves each year.
The formula
fuel per year = distance × litres per km × price per litre electricity per year = distance × kWh per km × price per kWh payback (years) = extra price ÷ (fuel per year − electricity per year)
Worked example
Driving 15,000 km a year, fuel costs 1,755.00 at 6.5 L/100 km and 1.80 a litre; electricity costs 637.50 at 17 kWh/100 km and 0.25 a kWh. The electric car saves 1,117.50 a year and pays back its 5,000 higher price in 4.5 years.
Sources
- US EPA and Department of Energy, fueleconomy.gov Official electric car energy use, measured from the wall, so charging losses are included.
- Commission Regulation (EU) 2017/1151 (WLTP) The European test for fuel and electricity use.
- NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B Exact conversion factors for US customary units.
- Weights and Measures Act 1985, Schedule 1 1 UK gallon = 4.54609 litres.
Sources checked September 29, 2026. 8 automated tests check its answers on every change.
About the electric vs gas car cost calculator
An electric car usually costs more to buy and less to run. This calculator puts a number on the second part: what you spend on fuel in a year against what the same distance costs in electricity, and how long the difference takes to cover the higher price.
The biggest factor is where you charge. Charging at home, especially on a cheaper night rate, is what makes electric driving cheap. Public fast chargers often cost two to three times the home price per kWh, and a car charged mostly at them can cost as much per mile as a petrol car. If you use them often, enter an average of the two prices.
Official figures for energy use include the losses while charging. Real use rises in cold weather, at motorway speeds and on short trips, for electric cars more than petrol ones, so the trip computer after a few months is the best number to use.
Fuel is not the only running cost. Electric cars need less servicing, with no oil changes and less brake wear, but can cost more to insure, and both lose value at different rates. Taxes and incentives differ a lot by country. Treat the payback time as a guide to the fuel part of the decision.
Questions people ask
How much does an electric car save on fuel?
Driving 15,000 km a year, a car using 6.5 L/100 km at 1.80 a litre spends 1,755 on fuel. An electric car using 17 kWh/100 km at 0.25 a kWh spends 637.50, saving 1,117.50 a year.
How much does it cost to charge an electric car per mile?
Multiply its kWh per mile by your electricity price. At 30 kWh per 100 miles and 0.17 a kWh, about 5.1 cents a mile.
Is an electric car cheaper if I only use public chargers?
Often not by much. Fast charging can cost two to three times home electricity, which can bring the cost per mile close to a petrol car.
Does this include charging losses?
Yes, if you use official figures: EPA and WLTP measure energy from the wall, including what is lost while charging.