Ten minutes shows your typing stamina: how well your speed and accuracy hold when your hands and focus tire.
Long tests are the closest thing to real work: a report, a transcript, an exam passage. Over ten minutes most people lose a few words per minute and make more mistakes towards the end. The chart on the results page shows exactly when that starts, and the time cards show whether the lost time went to mistakes, pauses or slower fingers.
Take a short break before you start, sit comfortably, and keep a steady pace rather than racing the first minute.
Stamina is mostly about staying relaxed. Tension in the shoulders, wrists and fingers wears you out long before the clock does, so check your posture before you start and let your hands rest lightly on the home row.
Work up in steps: a few days of five-minute tests, then a ten-minute test once or twice a week. After each one, compare the first and last minutes on the speed chart. If accuracy falls at the end, slow down slightly in the second half; if speed falls but accuracy holds, it is concentration, which improves with regular longer sessions. Short breaks between tests matter too: a tired typist practises mistakes.
Concentration and hands tire. A drop of 5 to 10% is common; regular longer tests make it smaller.
Press Esc to restart. A test that does not run its full time is not counted.