EV vs Petrol Cost Calculator
Compare yearly energy cost and use-phase emissions for an electric and petrol car. Select metric, US or UK units so gallon and fuel-economy conventions are handled correctly.
km
kWh/100 km
/kWh
L/100 km
/L
1,024 / year
Energy cost: EV 432 vs petrol 1,456 · Emissions: EV 1,319 kg vs petrol 2,975 kg CO₂e/year
How it's calculated
The tool converts both vehicles to common base units (kWh and litres), then calculates cost and emissions in parallel:
EV cost = annual EV kWh × electricity price
petrol cost = annual fuel volume × petrol price
emissions = annual energy or fuel × selected lifecycle factor
Monetary results use the local-currency prices you enter. The grid choices use 2025 lifecycle intensity data published in 2026. The petrol factor is the UK Government 2026 average blend including well-to-tank emissions. These are planning estimates, not a full vehicle lifecycle assessment.
Accuracy and limitations
- Use EV consumption measured at the charging point when possible. A dashboard-only figure may omit charging losses and understate electricity use.
- US mpg and imperial mpg are different. The unit selector converts each gallon definition exactly before comparing costs and emissions.
- The result compares energy cost and fuel-cycle/use emissions. Purchase price, maintenance, battery and vehicle manufacture, finance, tax and insurance are outside the boundary.
Frequently asked questions
How is the EV running cost worked out?
The calculator first normalises your selected metric, US, or UK units. EV energy use is multiplied by the electricity price. Petrol volume is multiplied by the matching per-litre, US-gallon, or imperial-gallon price, so UK and US mpg are never mixed.
Does this include purchase price, insurance or servicing?
No — this compares fuel/energy running costs only. Purchase price, insurance, and maintenance differ by model and are not included here.
Why are the EV emissions not zero?
Charging uses grid electricity. The estimate multiplies charging energy by the lifecycle grid factor you select. The petrol result includes fuel production and use. Vehicle and battery manufacture are excluded from both sides.