WattPayback

Blog · 2026-02-26 · 6 min

What it actually costs to charge an EV at home

Wall energy, charging losses and day/night tariffs explain most of the gap between brochure kWh/100 km and your bill.

From road to wall

Energy from the wall ≈ (km/100) × (kWh/100 km) ÷ charging_efficiency

Charging losses of 10–15% (efficiency 85–90%) are a normal planning band — not a universal constant.

Tariffs dominate

A night rate at a third of the day rate usually beats shaving a few percent off vehicle consumption. If you cannot charge off-peak, compare honestly against petrol with the EV charging calculator.