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kWh/100 km explained: the EV version of L/100 km

By RoadCost Editorial4 min readUpdated

kWh/100 km is the electric equivalent of L/100 km. It tells you how much energy the car uses to cover 100 kilometres. Lower is better, and the cost calculation is direct.

Quick answer

Cost per 100 km = kWh/100 km × price per kWh. If a car uses 18 kWh/100 km and electricity costs 0.30 per kWh, the energy cost is 5.40 per 100 km.

In this guide

  1. 1. The definition
  2. 2. A worked example
  3. 3. Battery side vs grid side
  4. Questions

Key takeaways

  • Lower kWh/100 km is better.
  • Cost per 100 km is a simple multiplication.
  • Battery-side and grid-side figures are not the same.

The definition

A kilowatt-hour is a unit of energy. A 100 km figure tells you how many of those units the car uses over that distance. It is a consumption measure, like L/100 km.

The number can come from the car's dashboard, a test cycle or a charging session. Those sources may not use the same boundary, so compare like with like.

energy used = km × (kWh/100 km) ÷ 100
cost = energy used × price per kWh

A worked example

Suppose an EV uses 16 kWh/100 km and you drive 250 km. Energy used = 250 × 16 ÷ 100 = 40 kWh. At 0.30 per kWh, the cost is 12.00.

If charging losses are included, the grid energy will be higher than the battery energy. That is why the price you pay at the meter is not always the same as the energy added to the battery.

Battery side vs grid side

The car's dashboard usually reports battery-side energy. The charger or electricity meter reports grid-side energy. Charging losses sit between them.

For a cost estimate, start with the meter reading or apply a charging-efficiency figure. Do not add losses twice.

Questions

Is 18 kWh/100 km good?
It is a reasonable figure for many EVs, but vehicle size, weather and speed matter. Compare with similar cars and similar conditions.
How do I convert kWh/100 km to mi/kWh?
Convert kilometres to miles and invert the relationship. Our EV efficiency converter does this without unit mistakes.
Does kWh/100 km include charging losses?
It depends on the source. Dashboard figures are often battery-side; meter-based figures include losses.

Sources

Try the calculator

EV charging cost calculator

Turn energy use and price per kWh into a charging estimate.

Related guides

mi/kWh vs km/kWh: EV efficiency units made simple

Convert miles per kWh to kilometres per kWh and kWh/100 km, and understand which direction means better efficiency.

EV charging losses explained

Why the electricity you pay for is not all stored in the battery, the charging-loss formula, and how to avoid double counting.

Home vs public EV charging cost

Compare home and public charging on all-in cost per kWh, including session fees, charging losses and convenience.

A note on prices and rules

This guide explains arithmetic and units. It does not publish live fuel prices, electricity tariffs or changing tax rules. Use your own price and check official sources for anything that changes.

Page last reviewed: . Formulas are covered by automated tests. Prices are inputs, not live data.