Online Tool Store
EV vs Petrol Cost Comparison
Enter your annual mileage, electricity/petrol prices, and vehicle efficiency to compare running costs between an electric and petrol vehicle.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
How EV vs Petrol Cost Comparison works
- Enter your annual mileage, along with electricity price and EV efficiency (in kWh per 100 miles).
- Enter petrol price and your petrol car's fuel economy (in mpg).
- The tool computes each vehicle's annual fuel cost and cost per mile, updating instantly as you adjust any value.
- It reports the annual savings (or extra cost) of driving electric at your entered prices.
The formulas
EV annual cost: (miles ÷ 100) × kWh/100mi × price per kWh.
Petrol annual cost: (miles ÷ mpg) × price per gallon.
Both reduce to a straightforward "distance ÷ efficiency × price" calculation — the only real complexity is that EV efficiency and petrol efficiency are conventionally expressed in opposite directions (energy per distance vs. distance per unit fuel), so the formulas look different even though they answer the same question.
FAQ
Does this include the purchase price difference between an EV and a petrol car?
No — this compares fuel cost only (electricity vs. petrol) for a given annual mileage. It deliberately leaves out purchase price, incentives, insurance, and maintenance, which vary too much by model, location, and incentive program to estimate honestly here; treat this as one input to a larger decision, not the whole picture.
Why does it ask for kWh per 100 miles instead of "miles per kWh"?
kWh/100mi is the efficiency figure most EV window stickers and spec sheets actually publish (mirroring how mpg works for petrol cars) — a lower number means a more efficient EV, using less electricity to cover the same distance.
Home charging is usually cheaper than public charging — which does this assume?
Whatever price you enter — the calculator doesn't assume a source. If you mostly charge at home, use your utility's per-kWh rate; if you rely on public DC fast charging, that's typically several times more expensive per kWh, so use that rate instead to get an honest comparison for your actual charging habits.
How we compare
| Feature | Online Tool Store | A back-of-envelope estimate | A manufacturer's marketing calculator |
|---|---|---|---|
| No file upload — runs in your browser | ✓ | N/A | ✗ |
| No sign-up required | ✓ | ✓ | ✗ |
| Free, no watermark | ✓ | ✓ | ✗ |
A manufacturer's calculator usually assumes their own vehicle's numbers and average national prices. This one uses your actual mileage, your actual local electricity and petrol prices, and your actual vehicle's efficiency — nothing pre-filled in a way that favors a particular model.