How to test your keyboard
- Press each key once, row by row.
- Keys that work turn light blue. The key you’re holding turns solid blue.
- Any key that stays grey after you press it didn’t register. It may be dead, disconnected, or mapped to something else.
- The panel above shows the last key, plus its
event.code, the physical key identifier your browser reports.
Keys that aren’t on the drawn layout (like media keys or a numpad) are listed under “Also detected”.
What the results mean
| Symptom | Likely cause |
|---|---|
| Key never lights up | Dead switch, dirt under the keycap, or a broken connection |
| Key lights up as a different key | Wrong layout setting in your OS, or remapping software |
| Key stays solid blue after release | Sticky or stuck key, or debris under the cap |
| Key works only when pressed hard | Worn switch or a membrane problem |
| Several keys in a row fail together | Matrix or ribbon cable fault (common in laptops) |
Quick fixes to try
- Dirt or crumbs: turn the keyboard over and tap it gently, or use compressed air at an angle.
- Sticky keys after spills: on mechanical keyboards, remove the keycap and clean around the switch with isopropyl alcohol (power off first).
- Wrong characters: check your keyboard layout in your operating system’s language settings.
- Wireless lag or missed keys: replace the batteries and move the receiver closer, ideally with a USB extension.
If keys work but sometimes type twice, run the key chatter test.
Frequently asked questions
Why don't the F keys or media keys show up?
Some laptops send F1–F12 as media or brightness keys unless you hold Fn. Some keys are also handled by your operating system before the browser sees them. Try holding Fn, or switch the Fn-lock setting.
Does it work with non-English keyboard layouts?
Yes. The tester uses physical key positions, so it works with any layout. Labels show the US layout, but the key you press lights up in the same physical position.
Why doesn't Print Screen light up?
Most browsers and operating systems don't pass the Print Screen key-down event to web pages. We detect it on key release where possible and list it below the keyboard.
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