Hardware check before a meeting
Before an important video call, use the mic test to check your input level and how you sound, and the webcam test to see the real resolution and frame rate your camera delivers. Your browser will ask for permission; if you denied it earlier, re-enable camera and microphone access from the padlock icon in the address bar. Audio and video are processed only in your browser and are never recorded or sent anywhere. If you use a headset, check which microphone your system has selected.
Buying a new or used device
The keyboard test lights up each key on an on-screen keyboard as you press it, so you can quickly find dead, sticky or ghosting keys. The dead pixel test fills the screen with solid colours to reveal pixels that stay dark or stuck on one colour, and includes a flashing fixer you can try on stuck ones. When buying a used laptop or monitor, running both tests in front of the seller avoids arguments later. Turn brightness up to make small defects easier to spot.
Speed and reflex tests
The typing speed test measures your words per minute and accuracy over one, three or five minutes; if you want to get faster, focus on accuracy first and speed will follow with regular practice. The CPS test counts your clicks per second, and the reaction time test measures how quickly you respond to a visual or audio cue in milliseconds. Results are affected by your mouse, screen refresh rate and browser latency, so use the same setup when comparing scores.