Keyboard Tester – Test your keyboard online

A Keyboard Tester checks in your browser whether every key on your keyboard registers. Select the key layout (ANSI or ISO) and size above, click in the test area and press each key once. Pressed keys light up and remain marked green afterward. The counter shows how many keys have been detected, while the Not Yet Detected list shows the rest. The tester also displays key, code and keyCode for the last key, measures rollover and detects double presses.

Yes. This keyboard test is free and requires no installation or account. It runs directly in Chrome, Edge, Firefox and Safari on Windows, macOS and Linux. Only your browser processes the key events: nothing is uploaded or saved, and everything disappears when you close the page. A browser cannot measure polling rate or input lag; you need the manufacturer's software for that. Keyboard Tester, Key Tester, Keyboard Checker and keyboard test all refer to the same tool.

Press a key in the test area and the tester displays it under Last Key: key is the character produced by your language layout, code is the physical position (such as KeyA or Numpad7), and keyCode is the legacy numeric value. You also see its position (left, right or numpad), hold duration in milliseconds and whether key repeat was active. For games and shortcuts, code is the most reliable value because it does not depend on the layout. If a key shows nothing here, its signal is not reaching the browser.

If no keys light up even though the test area is active, no signal is reaching the computer. Check the cable, USB port, wireless receiver, battery or Bluetooth connection. If only one key stays gray, dirt, a worn switch or an intermittent connection is usually the cause. Browsers cannot report some keys, though: the keyboard processes the Fn key internally and never sends it; the operating system may intercept the Windows or Cmd key; and the system handles shortcuts such as Ctrl+W or Alt+F4 before the page can see them. On Windows, the Print Screen key usually reports only its release, but the tester still counts it as tested.

In that case, the keyboard is usually not faulty. Press the key in the test area and compare code and key under Last Key: code identifies the key's position, while key is the character your operating system produces. The diagram uses US layout labels. If the key lights up in the right place but key shows a different character from the one printed on your key, your system is set to a different keyboard layout, such as English instead of German. Change it in your language or keyboard settings. If letter keys on a laptop report codes such as Numpad7, the built-in numeric keypad is active.

Rollover tells you how many keys can be detected at once. Many keyboards report six keys plus modifiers such as Shift and Ctrl over USB (6KRO); gaming keyboards with N-key rollover (NKRO) report significantly more. Hold down as many keys as possible in the tester: the highest value under Rollover shows your keyboard's limit. It is often lower over Bluetooth and some wireless modes than over a cable. Ghosting means that certain key combinations cause a key to go missing or one you did not press to appear. Test the keys you use together in games, such as W, A, Shift and Space: if all of them light up and no extras do, everything is working.

A double press occurs when a key registers one press twice. The tester counts it as a double press if the same key is registered again less than 40 ms after release, and marks it orange. Press the suspect key slowly several times. If it registers more than once per press, the switch is usually worn or dirty. If Last Key only shows Key repeat: yes while you hold it down, that is your system's normal key repeat, not a double press. If compressed air or careful cleaning with isopropyl alcohol does not help, you can replace the switch without soldering on a hot-swap keyboard. The threshold is a rule of thumb, not proof for a warranty claim.

Yes. Under Key Layout, choose ANSI (US) or ISO (Germany). Under Size, choose Full-size, TKL without a numpad, or Compact with just the main key block for small keyboards such as 60% models. Keys are detected by position, so the test works with QWERTZ, QWERTY and AZERTY. The diagram uses US layout labels; you can see the character from your layout under key. On a Mac, the tester shows Cmd, Option and Control with their symbols. On smartphones and tablets, you need a keyboard connected by USB or Bluetooth.