EV Cost per km Calculator
Calculate the running cost per km of your electric vehicle.
Compare home vs public charging costs and see annual fuel savings vs petrol.
The running cost of an electric car comes down to one short piece of arithmetic, and the answer is usually low enough that people assume they have made a mistake.
The formula:
Cost per km = kWh per 100 km × electricity rate ÷ 100
Consumption comes off the spec sheet or, better, the car’s own lifetime average display. The rate is whatever your utility charges per kWh. Dividing by 100 turns a per-100-km figure into a per-km one. Every figure this page reports is in the currency you type in, so enter both prices in the same one and the comparison holds.
Worked example:
A Tesla Model 3 averaging 14.9 kWh/100 km, electricity at 0.15 per kWh.
- Per km: 14.9 × 0.15 ÷ 100 = 0.022
- Per 100 km: 2.24
The same trip in a petrol car using 7 L/100 km at 1.60 a litre costs 7 × 1.60 ÷ 100 = 0.112 per km, or 11.20 per 100 km. On those figures the electric car runs at about a fifth of the cost, and once charging losses are added it settles around 4.6 times cheaper.
Charging losses, which nearly every comparison ignores
The kWh figure on the spec sheet is measured at the battery. Your meter counts what goes into the wall, and roughly 10% of it is lost as heat in the charger and cables. AC home charging typically loses 8 to 12%; DC rapid charging is closer to 5 to 10% but costs far more per kWh in the first place. This calculator shows both the battery-side figure and a wall-side figure with 10% added, because the wall-side one is what actually appears on the bill.
Typical consumption, for a sanity check:
- Small EV (Leaf, Bolt): 14 to 17 kWh/100 km
- Mid-size (Model 3, Ioniq 6): 13 to 16 kWh/100 km
- Large SUV or truck (Model X, Rivian): 20 to 28 kWh/100 km
Cold weather is the big variable those numbers hide. Below freezing, expect 20 to 40% worse consumption, because cabin heat comes out of the same battery rather than out of waste engine heat.
Where you charge changes the answer more than what you drive:
- Home overnight on an off-peak tariff is almost always cheapest
- Public AC (Level 2) usually runs 20 to 50% above a home rate
- DC rapid charging is often 2 to 3 times the home rate, which can erase most of the saving against petrol
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.