What do I do if my laptop keyboard has stopped working?

The checks that separate a stuck setting from a dead ribbon cable, in the order that finds the free fixes first — including the one that fools almost everyone.

Difficulty: beginner
Time: 20 min
Read: 5 min
Safety: caution

Short answer

Plug in a USB keyboard first: if that works, the machine is fine and the fault is the built-in keyboard or its driver. Before assuming hardware, check the obvious impostors — a stuck Fn lock, Filter Keys switched on accidentally, or the wrong input language. A full shutdown, not a restart, clears a surprising number of these because fast startup can carry the fault across.

A laptop keyboard failing completely is far less common than it appears, because several settings produce something that looks identical. Filter Keys, which ignores brief or repeated keystrokes, can be switched on by holding the right Shift key for eight seconds and leaves a keyboard that appears dead or wildly unreliable. A stuck Fn lock turns the number row into function keys. A changed input language turns the keyboard into a different layout. All three look like hardware and none of them are.

Safety

If anything has been spilt on the keyboard, shut the laptop down immediately, unplug it, and do not switch it back on to test it. Liquid plus power is what destroys boards. Turn it upside down to drain, and get it looked at rather than drying it with heat.

Step by step

Try an external USB keyboard.This single test splits the problem in half. If the external one works normally, the computer, the operating system and the ports are all fine and the fault is confined to the built-in keyboard or its driver. If the external one also misbehaves, the problem is system-wide.
Do a full shutdown, not a restart.On Windows, fast startup means a normal shutdown is really a partial hibernation and can carry a fault across. Hold Shift while clicking Shut down, or use shutdown from the command line, to force a genuine cold boot. On a Mac, shut down fully and leave it a few seconds.
Check the accessibility settings.Filter Keys on Windows, and Slow Keys on macOS, both ignore keystrokes deliberately and both can be triggered accidentally. Look in accessibility settings and turn them off. This is the single most common cause of a keyboard that seems dead but is not.
Check Fn lock and the input language.Many laptops have an Fn lock, often Fn plus Escape, that inverts the function row. Separately, an input language switch — usually Windows plus Space, or a keyboard shortcut on macOS — changes the layout so keys produce the wrong characters. The catalogue's guide on wrong keyboard characters covers the layout case in detail.
Reinstall the keyboard driver on Windows.In Device Manager, find the keyboard, uninstall the device, and restart. Windows reinstalls the standard driver automatically. It costs nothing and fixes a driver that has been corrupted by an update.
Test it outside the operating system.If you can get into the BIOS or UEFI setup screen at startup, or into the macOS recovery or startup options, the keyboard is being read by the firmware. If it works there and not in the operating system, the fault is definitely software. If it does not work there either, it is hardware.
Look for a physical cause.Crumbs and debris under a key, a key that has popped its clip, or a spill that has dried leaving residue. A can of compressed air with the laptop held at an angle clears a lot. Do not use a vacuum cleaner on a keyboard, which can generate static.
Accept the hardware answer when the evidence points there.If an external keyboard works, the firmware screen does not respond, and a cold boot changes nothing, the ribbon cable or the keyboard membrane has failed. On most laptops the keyboard is a replaceable part, and a repair shop can quote. In the meantime an external keyboard is a perfectly workable stopgap.

Common mistakes

Using a hairdryer on a spill — Heat drives liquid further into the machine and can warp components. Draining and airing at room temperature, then a professional clean, is the approach that saves boards.
Reinstalling the operating system to fix a keyboard — If an external keyboard works and the firmware screen does not, no reinstall will help, because the fault is physical. The external keyboard test tells you this in thirty seconds.

If it doesn't work

Only some keys do not work

Cause: Debris, a failed membrane section, or a stuck key — Fix: Partial failure is more often physical than software. Clean around the affected keys, and check whether the dead keys are adjacent — a contiguous group usually means one trace or one section of the membrane.

Keyboard works in the firmware screen but not in Windows

Cause: Driver or accessibility setting — Fix: Reinstall the keyboard driver and check Filter Keys. The firmware test has already proved the hardware is fine, which saves a repair bill.

Types the wrong characters rather than nothing

Cause: Input language or layout — Fix: Not a hardware fault at all. Check the language indicator in the taskbar or menu bar.

Keys repeat or stick

Cause: Debris, or a repeat-delay setting — Fix: Clean first, then check the keyboard repeat settings. A single sticky key can generate a stream of characters that makes the whole keyboard unusable.

Stopped working right after a spill

Cause: Liquid damage — Fix: Power off immediately, unplug, invert to drain, and take it to a repair shop. Sugary or salty liquids corrode traces over days, so this is time-sensitive and not something to leave until it dries.

Numbers appear when typing letters

Cause: Number lock active on a laptop without a separate numeric keypad — Fix: Some compact laptops overlay a numeric keypad on the letter keys. Fn plus Num Lock turns it off.

Questions people ask

Is it worth replacing a laptop keyboard?

It depends on the machine. On many laptops it is a straightforward part and a modest repair; on some ultrabooks the keyboard is bonded into the top case and the repair costs a significant fraction of the machine's value. Get a quote before deciding, and weigh it against simply using an external keyboard.

Can a Windows update break a keyboard?

It can break the driver, which looks identical from the outside. Uninstalling the keyboard device in Device Manager and restarting lets Windows reinstall a clean driver, and it is a two-minute test.

Why does my keyboard work sometimes and not others?

Intermittent behaviour usually means a physical connection — a ribbon cable that is not fully seated, or a cable damaged by repeated opening and closing of the lid. It can also be heat-related, in which case it will correlate with how long the machine has been on.