How to use the keyboard tester
- Click the keyboard layout so it has focus.
- Press each key on your keyboard. The key lights up while you hold it and stays marked once it has worked.
- Watch the counter: when every key is marked, your whole keyboard has been checked.
- Use Reset to start again, for example after cleaning a key.
The panel under the board shows details of the last key: the character it produced (key), its physical position (code), whether it was a left, right or number pad key, and which modifier keys were held at the same time.
What you can find
Dead keys
A key that never lights up, no matter how you press it. Press it straight down in the center and near the edges. If it only works sometimes, dirt under the key is a common cause.
Stuck or repeating keys
If a key stays lit after you let go, or the modifier line says "auto-repeat" without you holding anything, the switch may be stuck. Gently press it a few times, or clean around it.
Ghosting and rollover
Many keyboards cannot report every combination of keys pressed at the same time. Hold several keys together, such as the ones you use in games, and check that each one lights up. The Held now counter shows how many keys the browser sees at once. Gaming keyboards often handle more keys at once than basic office keyboards.
Keys a web page cannot see
Some keys never reach the browser, so they cannot light up here even if they work. Fn is handled inside the keyboard itself. Media, volume and brightness keys are often taken by the system. Some shortcuts are reserved by the browser or the system, such as the ones that close a tab or switch between apps. The Meta key (the one with the system logo) may open a menu instead of reaching the page. None of this means your keyboard is faulty.
While the layout has focus, keys that would normally scroll or navigate the page, like Space, the arrows, Page Up and Page Down, are held back so the page stays still. Tab is not blocked: it moves focus away from the tester as usual, so you can always leave with the keyboard. Click the layout to return.
Testing on a phone or tablet
On-screen keyboards on phones do not send physical key codes in a reliable way, so the layout cannot light up correctly for them. Use the typing box under the board instead: tap it, type, and check that each character appears. An external keyboard connected to a tablet usually works with the full layout.
Tips
- Work row by row so you do not miss a key.
- Test Num Lock on and off: some number pad keys act as arrows when it is off.
- Before cleaning, unplug the keyboard or switch it off. Use compressed air or a soft brush, never liquid poured onto the keys.
Next, see how fast you can press with the CPS test or how quickly you respond with the reaction time test.
Questions
Why does a key not light up?
Either the key does not send a signal, or the browser or system keeps that key for itself. Keys like Fn, some media keys and certain shortcuts never reach a web page. If an ordinary letter or number stays dark, the key may be faulty.
Why does Print Screen only light up when I let go?
On many systems Print Screen only sends a key release to the browser. The tester counts that too.
How do I test for ghosting?
Hold several keys at once and watch the Held now counter and the layout. If a key you are holding does not light up, or a key you are not pressing appears, your keyboard has a limit on simultaneous keys for that combination.
My layout is not US. Does it still work?
Yes. The tester reads the physical position of each key, so a key lights up where it sits on a US layout even if your keyboard prints a different character on it. Keys that do not exist on a US layout are listed under the board.