DeviceJig

Keyboard Test

Check that every key works, how many keys register at once, and whether any key double-types.

`1234567890-=Bksp
TabQWERTYUIOP[]\
CapsASDFGHJKL;'Enter
ShiftZXCVBNM,./Shift
CtrlSysAltSpaceAltSys≡Ctrl
Keys tested
0
Most held at once
0
Last key
None
Double-typing events
0

Result

Press any key

Each key lights up once it reaches this page. Then hold many at once to check rollover.

Your keyboard doesn't have a key on the map? Click that key to leave it out. Using only a keyboard? Press Esc twice to pause capture, then Tab works.

30 ms

Limits of a browser: what this can't tell you
  • Your system takes some keys before a page can see them: Fn, Print Screen on some systems, Cmd or Windows shortcuts, and media keys.
  • Rollover shows what reached the browser. Keyboards, USB modes and operating systems can cap it, and a blocked combination can depend on which keys you pick, so try several.
  • Ghost keys can appear on the map as keys you didn't press. Watch for those while holding many keys down.
  • Chatter shows up only if it gets past the keyboard's own filter. The 30 ms default is our rule of thumb.
  • On a phone or tablet, on-screen keyboards don't report physical keys, so this page needs a real keyboard.

Press keys and watch the map.

How to test your keyboard keys

  1. Choose your layout. Keys are matched by physical position, so the map works even if your labels differ.
  2. Choose the size. Pressing any number pad key also adds the pad to the map.
  3. Press every key once. Tested keys light up. Click any key your keyboard doesn't have to leave it out.
  4. Hold down as many keys as you can to check rollover, trying different groups of keys.
  5. Tap suspect keys repeatedly. Red with a cross means two presses came within the limit.

Rollover, ghosting and chatter

  • Rollover: how many keys register at once. Depending on its wiring, a keyboard can miss some combinations of 3 or more keys. A USB keyboard using the standard boot report sends at most 6 normal keys plus the modifier keys; some keyboards can report more.
  • Ghosting: a key you didn't press appears when you hold certain others. If that happens, you'll see it light up.
  • Chatter: one press registers as two. A release followed by a new press within the limit gets flagged. The 30 ms default is our rule of thumb, not a standard; move the slider if you tap very fast. A press made with the slider moved can't count as Passed on your report: set it back to 30 ms, press Reset and run every key again. Two or more events count as likely chatter.
  • Untested keys: the result lists keys still unpressed once there are few enough to read.

Common questions

Is there a way to test my keyboard?

Yes. Press each key on this page and watch it light up on the map. No download is needed, and the page also checks rollover and double-typing.

How can I test my keyboard keys?

Press them one at a time and look for keys that don't light up. If a key stays dark after several firm presses, and it isn't a special Fn or system key, the key may be faulty.

How do I run a keyboard diagnostic?

This page covers the common checks. For a laptop, the maker's own diagnostics can test further, but this quickly shows which keys reach the system.

Why does my keyboard type a letter twice?

That's usually chatter from dust or a worn switch. Clean under the keycap, raise the repeat delay in your system settings, and test here again.

Related tests

Privacy

Any page counting is cookie-free; see the privacy page. Results stay in this browser and join your device report.

Technical reference, read 2026-11-01: MDN: KeyboardEvent.code, USB-IF: HID 1.11, appendix B (6 keys in a boot report).

Windows is a trademark of Microsoft Corporation. Cmd refers to a key on keyboards made for Apple Inc. computers. DeviceJig is independent and is not affiliated with these companies.

All 11 tests, by device

Find your device, pick the numbered part you want to check.

Screen

Mouse

Keyboard

Controller

Speakers

Headphones