Start the clock with actual typing
Pressing Start arms the input without spending race time. The first typed character starts the monotonic clock. The timer continues if you hesitate or leave the field; hiding the tab marks the run interrupted.
The passage preview follows the current position and marks matching and mismatching characters. Direct insertion and normal deletion are accepted. Paste and other bulk-replacement input are excluded because this is a typing exercise.
Separate three useful measurements
Correct-character WPM measures matching characters currently present in the input, using five characters as one word. Gross WPM measures all inserted characters, including corrections. Accuracy measures how many of those insertions matched their expected position.
Correcting a typo can improve the current text without erasing the fact that the wrong character was inserted. The error record keeps that information so a later drill can target the relevant key or pair.
Compare equivalent conditions
Different sites can use different word, accuracy and error-penalty definitions. Treat this game’s formulas as its own stated conventions rather than assuming a number is interchangeable with another service.
Use the same duration, passage and input setup when comparing runs. Short or interrupted attempts remain useful practice but are not accepted as comparable ghost records. No score is a certificate or guaranteed prediction of work performance.