Free tools / Keyboard tester

Keyboard Tester

Find dead, stuck and chattering keys. Press each key and watch it light up, on a laptop or a desktop keyboard.

FreeRuns in your browserNothing uploaded

Keys tested

0 of 0

Held now

0

Peak held together

0

Stuck keys

None

held tested stuck not yet pressed

Press every key once. Unlit keys are dead.

Key history

Fn, media, backlight and some power keys are handled by the keyboard itself and never reach the browser, so they cannot be tested here. Everything runs locally in your browser and nothing is uploaded.

How to use the keyboard tester

1

Press every key once. Click the tester or just start typing. A key turns orange while it is held and stays green once it has registered. Work along each row, including the F keys, arrows and the number pad.

2

Match the layout. Switch between ISO UK and ANSI US if the on-screen keyboard does not match yours. The tester reads the physical key position, so it works whatever language your keyboard is set to.

3

Check for ghosting. Hold several keys at once and watch the held-now counter. It shows how many keys the browser sees pressed at the same time.

4

Read the history strip. It records the last keys pressed in order, which helps when a key registers twice from one press or sends a different character to the one printed on it.

What the results mean

A key that stays unlit. After a firm press, the key is dead. On a laptop that is usually a failed dome or a break in the membrane under the keycap. On a desktop mechanical board it is normally a single switch.

A key flagged as stuck. It has been reported as held for more than three seconds. If you are not touching it, the switch or membrane is stuck, often because of liquid, crumbs or a damaged switch.

A key that appears twice in the history. From one press, the switch is chattering. It is a common fault on worn mechanical switches and shows up as doubled letters when you type.

The held-now count stops climbing. While you are still pressing keys, you have reached the rollover limit of the keyboard or its connection. That is a design limit, not a fault. Many keyboards cap simultaneous keys over USB or Bluetooth.

Fn and media keys do nothing. That is normal. They are handled by the laptop firmware and are never sent to the operating system, so no browser tester can see them.

When it is a repair job

On a laptop, a handful of dead keys is almost always a keyboard replacement rather than an individual key fix, because the keys are one sealed unit. We replace keyboards on all the main laptop brands at our Kings Cross workshop, including models where the keyboard is bonded to the top case. If you have spilled something on it, switch off, unplug and bring it in as soon as you can, before the liquid reaches the board.

Dead or sticky keys on a laptop?

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Keyboard tester: your questions answered

The tester says my Fn key is not working. Is it broken?−

Probably not. Fn is handled inside the keyboard and is never sent to the operating system, so no browser tester can see it. Test it by pressing Fn with a brightness or volume key and checking that the laptop responds.

Why do some keys open a browser feature instead of registering?+

The tester blocks the usual page shortcuts while you use it, but a few combinations are reserved by the browser or the operating system, such as closing a tab or the Windows key on its own. Those still register in the tester before the shortcut fires.

What does the held-now count tell me?+

How many keys the browser currently sees pressed together. It is a quick check for ghosting and rollover. If keys drop out while you hold others, the keyboard or its controller cannot handle that combination.

Can a stuck key be cleaned?+

Sometimes. On a desktop board a keycap can be removed and the switch cleaned. On a laptop the keycaps are fragile and the fault is usually below them, so it is safer to have the keyboard replaced.

Is my typing recorded?+

No. The tester only lights the on-screen key and keeps a short history on the page. Nothing is sent anywhere, and the history is cleared when you leave.

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Keys not working?
Laptop keyboards replaced at Kings Cross, usually the same or next day.

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