
A 10-minute typing test measures endurance: the speed and accuracy you can keep up over a long stretch of typing, like a real working session. Type random passages for ten minutes and see your results at the end.
Long tests are used for data entry, transcription and some clerical and government exams, where you type continuously for extended periods. They're also the most honest measure of your everyday speed, because nobody can hold a sprint pace for ten minutes.
Sit comfortably with relaxed wrists and settle into a steady rhythm from the first line instead of starting fast. When you make a mistake, fix it and move on without losing your flow. Expect your speed to drift down a little towards the end — that's normal fatigue, and it improves with practice.