How to use it
- Type the Battery capacity in kilowatt-hours, for example 75, from the car's specification.
- Enter the Usable share of the battery in per cent, for example 90. Enter 100 if the capacity is already the usable figure.
- Type the Consumption in kWh per 100 km, from the rating or from your own trips, for example 18.
- Read the Estimated range and the table Range at each charge level for the distance at 100, 80, 50 and 20 percent of the usable energy.
How the range is calculated
The car uses the usable energy of its battery. Multiply the capacity by the usable share: 75 kWh × 90 % = 67.5 kWh.
The distance is that energy divided by the consumption. At 18 kWh per 100 km the car uses 0.18 kWh per kilometre, so 67.5 kWh covers 67.5 ÷ 0.18 = 375 km.
A US label gives the consumption per 100 miles and the range in miles. One mile is 1.609344 km, so divide the kWh per 100 miles by 1.609344 to get kWh per 100 km.
Usable energy (kWh) = battery capacity (kWh) × usable share (%) ÷ 100
Range (km) = usable energy (kWh) ÷ consumption (kWh per 100 km) × 100What the figures mean
- The US label states the range as an approximate distance for a fully charged battery, in combined city and highway driving.
- The label also says that a given vehicle may or may not be able to travel 100 miles on a fully charged battery, so the figure is a guide, not a promise.
- The range figure is approximate, so compare figures that come from the same source.
What this calculator does not include
- Charging time, charging losses and the energy taken from the grid. Use the EV charging time calculator for those.
- Temperature, speed, load, climate control and driving style, which the calculator does not model.
- Battery ageing. Take the capacity and the usable share from the maker's specification.
Worked example: 75 kWh, 90 % usable, 18 kWh per 100 km
The usable energy is 75 × 90 ÷ 100 = 67.5 kWh. The estimated range is 67.5 ÷ 18 × 100 = 375 km.
The table gives the energy and the distance at each charge level. At 50 % of the usable energy the car holds 33.75 kWh and covers 187.5 km.
| Charge (%) | Usable energy (kWh) | Range (km) |
|---|---|---|
| 100 | 67.50 | 375.0 |
| 80 | 54.00 | 300.0 |
| 50 | 33.75 | 187.5 |
| 20 | 13.50 | 75.0 |
Frequently asked questions
How far can an electric car go on one full charge?
It depends on the energy the battery can use and on the consumption. Divide the usable kilowatt-hours by the kWh used per 100 km and multiply by 100: 67.5 kWh at 18 kWh per 100 km gives 375 km.
What is the usable share of the battery?
It is the part of the battery capacity that the car can use, as a percentage. Take it from the maker's specification, or enter 100 percent if the capacity you have is already the usable figure.
How do I convert kWh per 100 miles into kWh per 100 km?
Divide it by 1.609344, because one mile is 1.609344 kilometres. A figure of 30 kWh per 100 miles is about 18.64 kWh per 100 km.
Why is the range on the label different from my real range?
The label figure is an approximate distance for a fully charged battery in a set mix of city and highway driving. The label calls the figure approximate and says a given vehicle may or may not travel 100 miles on a fully charged battery, so real results can differ.
Does this calculator show how long charging takes?
No. It shows the distance the battery can cover. For the charging time, the grid energy and the cost, use the EV charging time calculator.
Does the calculator keep the numbers I type?
The page works in your browser and sends nothing to a server. The numbers stay in the page address, so a copied link shows the same figures.
Sources
- US EPA fuel economy label: text version for electric vehicles (archived January 2025)
- NIST SP 811, Appendix B.8: conversion factors (mile, horsepower, litre)
Figures and text last checked on Thursday, November 12, 2026.