Does this calculator include the higher purchase price of an EV?

No — it compares running (energy) costs only. EVs typically cost more to buy but less to run. To see the full picture, use this calculator to get the annual running-cost saving, then estimate how many years it takes for that saving to offset the higher purchase price. The true cost of owning a car calculator can help you factor in depreciation and total ownership costs for each option.

Why is my EV saving smaller than I expected?

Two common reasons: electricity prices vary a lot depending on whether you charge at home (cheaper) or at public fast-chargers (often much more expensive), and EV efficiency drops in cold weather and at motorway speeds. This calculator uses a single flat electricity price and a single efficiency figure. If you charge mostly at public chargers or drive a lot at high speed, your real EV cost will be higher than a home-charging estimate suggests.

Electric Car vs Petrol Running & Fuel Cost Calculator

Enter your annual mileage, EV efficiency, electricity price, petrol mpg, and fuel price to compare what each option actually costs you per year on energy alone.

Comparing the running cost of an EV against a petrol car

Fuel costs dominate the ongoing running cost of a car. An electric vehicle converts electricity into motion more efficiently than a petrol engine converts fuel, but whether that translates into savings depends entirely on local energy prices and how efficiently your specific car drives.

Worked example. Driving 10,000 miles/year in an EV at 3.5 miles/kWh and $0.17/kWh costs about $486 in electricity. The same mileage in a petrol car at 35 mpg and $3.50/gallon costs $1,000 in fuel. That’s a saving of roughly $514/year on energy alone.

The formula

EV annual cost = (annual miles ÷ miles per kWh) × electricity price per kWh
Petrol annual cost = (annual miles ÷ mpg) × fuel price per gallon
Annual saving = petrol annual cost − EV annual cost (negative means EV costs more)

This is an estimate — edit the assumptions for your situation

Efficiency and prices are the two inputs that swing the result most. Real-world EV efficiency is typically 10–20% lower than official figures due to heating, high-speed driving, and battery degradation. Electricity tariffs vary significantly between home and public charging. Petrol prices fluctuate weekly. Use conservative (worse) efficiency figures and check your actual electricity tariff before drawing conclusions.

Comparing a hybrid against petrol

This tool compares two options at a time, but you can use it for a hybrid vs petrol comparison too. Enter the hybrid’s real-world mpg on the petrol side and your regular petrol car’s mpg as the second figure, or set the EV side to the hybrid’s electric-only efficiency if you mostly drive short trips on battery. A hybrid’s advantage over a plain petrol car is smaller than an EV’s, so use your on-board trip-computer mpg for both to keep the comparison honest.

Key things to look up for accurate inputs

EV miles/kWh: Check real-world consumption from owner communities or apps like Plugshare, not just the manufacturer’s WLTP figure.
Electricity price: Use your home tariff’s unit rate — not the standing charge. If you charge partly at public chargers, use a blended rate.
Petrol mpg: Use your on-board trip computer reading for your typical driving mix, not the official combined figure.

EV vs Petrol Running Cost Calculator