Keyboard Test Online

No physical keyboard? Tap the keys below — that checks touch input and the on-screen layout. To test real switches, chatter and rollover, connect a keyboard to this device.

Not tested Held down now Works Chatter detected

Esc

F10

F11

F12

Backspace

Tab

[

]

Caps

;

Enter

Shift

Ctrl

Win

Alt

Win

Ctrl

PrtSc

ScrLk

Pause

Ins

Home

PgUp

Del

End

PgDn

↑

←

↓

→

Num

Enter

Coverage 0%

Test results

Last key

Character —

event.code—

event.keyCode—

Position —

Pressed at —

Held for —

Coverage

Tested by keypress 0

Tested by tap 0

Still untested 104

Total presses 0

Session time 0:00

Contact chatter

Repeat registrations 0

Shortest gap —

Threshold after release

Keys held now 0

Rollover (NKRO)

Simultaneous now (modifiers excluded) 0

Best result 0

USB boot protocol limit 6

Key history

How to test a keyboard

Press every key on your keyboard and watch the diagram above. A key that lights up green is sending its signal to the browser; a key that stays white is not being registered at all. The layout is a full 104-key ANSI keyboard — the typing block, the function row, the navigation cluster and the numeric keypad — so a fault on the numpad or on Print Screen shows up as clearly as one on the space bar.

What the tester measures

Dead and intermittent keys — anything left white after you have gone across the whole board.
Contact chatter — one press registering twice because the switch contacts bounce.
Stuck keys — a key that never sends its release event, reported after five seconds.
Key rollover (NKRO) — how many keys your keyboard can report at the same time.
Key codes — event.code, event.keyCode and whether the key came from the left, the right or the keypad.

Contact chatter, and why the threshold is 20 ms

When a mechanical switch closes, its contacts bounce for a few milliseconds before settling. A healthy keyboard's controller filters that out. A worn or dirty one lets it through, and one press arrives as two.

The tester flags a repeat only when a key goes down again less than 20 ms after it was released. The fastest human double-tap of one key is around 80–100 ms, so anything under the threshold is the hardware, not you. Raise the threshold to 30 or 50 ms to catch milder cases — and expect some of those to be your own fast typing.

Rollover and ghosting

Hold several keys at once and watch the rollover panel. Over USB, the boot protocol reports at most six keys plus modifiers, so six is a normal ceiling for an ordinary keyboard. Gaming keyboards that advertise NKRO report every pressed key at once and will go past ten here.

If keys stop registering well before six, that is ghosting — a limitation of the key matrix rather than a broken switch. It usually depends on which combination you press, so try a different group of keys before concluding anything.

If a key does not respond

Check that key capture is on — with it off, the browser handles Tab, F5 and the arrows itself.
Some keys never reach the browser at all: Print Screen, Fn and most media keys are handled by the operating system or by the keyboard's own firmware.
Try the keyboard on another device. If the key fails there too, it is the hardware; if not, look at drivers and layout settings.
On an ISO keyboard the extra key next to the left Shift has no cap on this ANSI diagram — it is still reported in the diagnostics below the panels.

FAQ

How do I test my keyboard online?

Press your keys one by one and watch the diagram: a key that works turns green, a key that does not respond stays white. The layout carries all 104 ANSI keys, including the numeric keypad and the navigation cluster, so you can check the whole keyboard rather than only the typing area.

Why does one key press register twice?

That is contact chatter: when a switch closes, its contacts bounce for a few milliseconds, and a worn switch lets the extra registration through. The tester counts a repeat only if the key goes down again less than 20 ms after it was released — a human cannot manage that, since the fastest double-tap of one key takes 80–100 ms.

How many keys can a keyboard register at once?

Over USB, the boot protocol reports at most six keys plus modifiers, so six is a normal ceiling for an ordinary keyboard. Modifiers travel in a field of their own and take no slot, which is why the test does not count them. Keyboards with NKRO report every pressed key at once and go past ten — but the figure shown is always a floor: it says how many keys you managed to hold down, not how many the keyboard can report.

Why do Print Screen or Fn not respond in the test?

Those keys often never reach the browser: Fn is handled by the keyboard firmware itself, while Print Screen and most media keys are intercepted by the operating system. No reaction here does not mean the key is faulty.

Can I test a keyboard on a phone?

Yes, if you connect a physical keyboard to the phone or tablet over Bluetooth or USB-OTG. Without one you can tap the keys on the diagram itself: that checks touch input and the layout, but not the physical switches.

Found an error in the calculation or the information?