WattPayback
Calculator

EV home charging cost calculator

Estimate annual home charging cost with day/night tariffs and compare against a petrol car.

Your situation

km/yr
kWh/100km
€/kWh
€/kWh
%

Defaults are starting points from typical published ranges — never facts. Change any value that does not match your situation.

%
L/100km
€/L

Estimate only. Based on the assumptions you entered. Get a site-specific survey before spending money.

Energy from wall

3,068 kWh/yr

EV annual cost

€466

EV cost / 100 km

€3.11

Petrol cost / 100 km

€11.05

Petrol annual cost

€1,657

Annual difference

€1,191

EV cheaper

Formula with your numbers

energy = 15000/100 × 18 / (88/100) = 3,068.2 kWh

blended_rate = 80% × 0.12 + 20% × 0.28 = 0.1520

ev_cost = energy × blended_rate = €466

petrol_per_100 = 6.5 × 1.7 = €11.05

Frequently asked questions

Why is charging efficiency less than 100%?+

AC/DC conversion, battery thermal management and cable losses typically consume 10–15% of energy drawn from the wall. Default 88% means divide by 0.88.

Is night charging always cheaper?+

If you have a time-of-use tariff with a genuine overnight trough, shifting charge sessions there usually dominates the annual cost. Without a cheap night rate the petrol comparison matters more.

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