How is WPM calculated?

One word is counted as five characters. Net WPM uses only correctly typed characters; raw WPM uses everything you typed.

Where is my best score stored?

Only in this browser. Nothing you type is saved or sent anywhere; just the best WPM per duration is remembered locally.

JavaScript is turned off. InspireTools processes files in your browser, so the tools need JavaScript to run.

Measure your typing speed in words per minute and your accuracy.