EV efficiency calculator: your real kWh per 100 km

How to read the result

Your efficiency is simply the energy you used divided by the distance. Energy used is your usable battery size times the percentage of charge the trip consumed, so a 60 kWh battery down 50% is 30 kWh. Divide by the miles (or km) driven and you get your real consumption — the honest figure to set against the WLTP number. From it we also project how far a full charge would take you at the same rate. Cold weather, motorway speed and climate control all push consumption up, so a winter motorway run reads far higher than a mild town commute.

Frequently asked questions

How do I calculate kWh per 100 km?

Take the energy you used, divide by the distance and multiply by 100. Using 18 kWh over 100 km is 18 kWh/100 km. Read the energy from the car's trip computer, or estimate it as your usable battery size times the percentage of charge the trip used.

What is a good efficiency for an electric car?

Most EVs sit around 15–22 kWh/100 km (roughly 3–4 mi/kWh) in real use. Small, aerodynamic cars in town can beat 15; large SUVs, motorway speeds and cold weather push past 22. Your own number matters more than any average — track it across the seasons.

Why is my efficiency worse than the WLTP figure?

WLTP is measured in mild, gentle lab conditions. Real driving — cold, fast roads, heating and climate control — uses more energy, so a figure 10–40% above the WLTP consumption is normal. Compare your result with the spec figure to see your personal gap.

Should I use the battery percentage or the trip computer?

Both work. The trip computer's kWh reading is the most direct; without it, the battery-percentage method (usable battery size × percent used) is a good estimate. For the cleanest reading, measure over a longer trip and avoid part-charges midway.