About this calculator

A single, focused tool for making sense of electric-vehicle efficiency numbers.

This site exists because electric-car efficiency is quoted in a confusing mix of units — miles per kWh, kWh per 100 miles, watt-hours per mile, MPGe — and most people just want to know two things: how efficient is this car, and what will it cost me to drive. The calculator converts between every common unit, works out MPGe using the EPA's 33.7 kWh-per-gallon standard, and turns your electricity price into a real cost per mile you can compare against gasoline.

Everything runs entirely in your browser. Nothing you type is uploaded, logged, or stored on a server. The numbers you enter never leave your device.

The tool is built and maintained by Marcio, an independent builder of small, practical web tools. It is an information tool, not financial or purchasing advice: the estimates depend on the prices and efficiency figures you provide, and real-world results vary with weather, driving style, and charging setup. Always confirm important decisions with your own bills and your car's dashboard readout.

Spotted a bug or have a suggestion? I would like to hear it — see the contact page.