The comparison, done honestly
Both sides of the comparison reduce to cost per kilometre. Petrol: cost = distance ÷ mileage × fuel price. EV: cost = distance × consumption ÷ (1 − charging losses) × electricity price, the loss factor matters because your meter bills the wall, not the battery.
Worked example: 1,000 km a month
| Petrol car | EV (home charged) | |
|---|---|---|
| Efficiency | 15 km/l | 15 kWh/100 km |
| Energy price | ₹100/litre | ₹8/kWh (+10% losses) |
| Monthly energy | 66.7 litres | ~166.7 kWh from the wall |
| Monthly cost | ₹6,667 | ₹1,333 |
That is ₹5,333 a month saved, an 80% cut in energy cost, ₹64,000 a year at this mileage. Running cost is not a close contest: home-charged electricity beats petrol per kilometre by a wide margin almost everywhere. The interesting questions are elsewhere.
Running cost is not total cost
An honest comparison admits what this page does not measure. EVs typically carry a purchase premium over the equivalent petrol car. Insurance can differ. Battery degradation is slow in modern packs but real, and resale values for EVs are still finding their level. None of that shows up in a running-cost figure, and a calculator that implies otherwise is selling you something.
The clean way to fold the premium in is payback framing: payback months = price premium ÷ monthly running-cost saving. A ₹3 lakh premium against a ₹5,333 monthly saving pays back in about 56 months. Drive 2,000 km a month instead and payback halves to about 28 months. This is why the EV case strengthens with mileage: the premium is fixed, the saving scales with every kilometre.
When each side tends to win
- EV wins clearly: home or workplace charging, above-average mileage, keeping the car 5+ years, city driving (regeneration helps consumption).
- Closer contest: low annual mileage (the premium takes years to recover), dependence on public fast charging at 2–3× home rates, or frequent long highway runs beyond comfortable range.
- Petrol can still win: very low mileage plus no home charging plus short ownership, the premium never pays back in fuel.
Getting your inputs right
Use realistic figures, not brochure ones. Petrol cars rarely achieve their claimed mileage in city traffic; EVs consume noticeably more at sustained highway speed and with climate control running. If you have a fuel-tracking habit or your EV's trip computer history, use those numbers. For the EV side, your electricity tariff matters more than any spec: a time-of-day plan charging overnight can drop your rate 20–40%, while public fast charging multiplies it, the EV charging cost calculator breaks that side down in detail, losses included.
For the petrol side on a specific trip, the fuel cost calculator gives per-trip and per-km figures. And if you are weighing the purchase premium as an investment decision, money spent now for a stream of monthly savings, the inflation calculator is a useful reminder that fuel prices have historically climbed faster than electricity tariffs, which quietly improves the EV case each year.
The bottom line
Run your actual numbers. For most people with home charging, the result is a running-cost saving large enough to pay back a reasonable purchase premium well within the ownership period, but the calculator will tell you if you are the exception, and that is worth knowing before the showroom visit, not after.