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Stuck Key Test

Shows every key your computer currently thinks is held down, with a live timer. Take your hands off the keyboard — anything still listed is stuck.

Take your hands off the keyboard

Nothing is held. Press a key to confirm the test is reading your keyboard.

Currently held — should be empty when you let go

Nothing held. That is what a healthy keyboard looks like.

Auto-repeat events — normal while held, a fault when not

No repeat events recorded. Hold a key for a second to confirm detection is working.

How to Find a Stuck Key

The test is one instruction: take your hands off the keyboard and look at the list. Every key the computer believes is currently held down appears there with a live timer. On a healthy keyboard the list empties the instant you let go. Anything that stays is stuck, and the timer tells you how long it has been stuck for.

That works because a keyboard reports presses and releases as separate events. A stuck key is one that sent its keydown and never sent the matching keyup — either the switch is physically held closed by debris or a broken stem, or the keyboard's controller lost track of the release. The distinction between those two is what the next section is about, and this page gives you the evidence to tell them apart.

Stuck modifiers are the ones that cause real damage, and they are also the hardest to spot without a tool like this. A stuck Shift makes everything uppercase. A stuck Ctrl turns every letter into a shortcut — press S and your browser tries to save the page. A stuck Alt or Meta opens menus or the app switcher on every keystroke. Because the symptom looks like software going wrong rather than a key going wrong, people reinstall drivers for days before checking. Modifiers are called out separately above for exactly that reason.

The second half of this page counts auto-repeat events. When you deliberately hold a key, the operating system sends a stream of repeat keydowns after a short delay — that is how holding Backspace deletes a whole line. This page records those (most tests filter them out) because a key repeating without being held is the signature of a runaway key. If the repeat counter is climbing for a key that is not in your held list, or that you are not touching, that key is firing on its own.

One thing this test deliberately handles: if you hold a key and then click away to another window, the browser never receives the keyup and the key would look stuck forever. The page clears its held-key state when the window loses focus, so a false alarm from alt-tabbing does not happen. That does mean you should keep this tab focused while testing.

Related faults have their own pages. A key that registers twice per press is chatter, measured by the double typing test. A key that does nothing at all shows up in the full keyboard test. Keys that drop out only when several are held together are a rollover limit, which the N-key rollover test measures.

Key Capabilities & Features

Live held-key list

Every key your computer currently believes is down, updated as you press and release.

Hold duration timer

Counts how long each key has been held. Past three seconds with your hands off the keyboard, it is stuck.

Modifier warning

Calls out a stuck Shift, Ctrl, Alt or Meta separately, because those break every other key rather than just one.

Auto-repeat counter

Records the repeat events most tests filter out, which is how you catch a key firing without being held.

Focus-loss handling

Clears held state when the window loses focus, so alt-tabbing with a key down does not create a false alarm.

Sticky Keys guidance

Explains the accessibility setting that mimics a stuck modifier exactly, and how to rule it out first.

How to Perform This Test

Click once on the page so the browser tab has keyboard focus, then keep this tab in front.:
Take both hands off the keyboard completely. The held-key list should be empty.:
If any key is listed with your hands off the keyboard, that key is stuck — read its timer and its name.:
Press and release each modifier in turn: both Shifts, both Ctrls, both Alts. Each should appear while held and vanish on release.
Watch the repeat counter for thirty seconds without touching anything. A climbing count means a key is firing on its own.:
Hold one key deliberately for a few seconds to confirm the timer and repeat counter are working, then release and check the list clears.:

Troubleshooting Common Hardware Issues

A key is listed but you are not touching it: that is the fault, confirmed. Pull the keycap and check for debris before anything else.
A modifier looks stuck but feels physically normal: check Sticky Keys. Pressing Shift five times toggles it, so it gets enabled by accident often.
The list will not clear after you alt-tabbed: click back into this tab. Held state is cleared on focus loss, so refocusing resets it cleanly.
Repeat count climbs while you hold a key: correct and expected. Auto-repeat is the operating system, not a fault. It only indicates a problem when the key is not held.
Nothing appears at all when you press keys: click once on the page. A newly loaded tab sometimes leaves focus in the address bar.
One key sticks only when the keyboard is warm: thermal expansion moving a marginal part. It will get worse rather than better.
Every key seems to stick: suspect software rather than twenty simultaneous switch failures. Check remapping tools, macro layers, KVM switches and remote-desktop sessions.
A wide key like Shift or Space sticks at one end only: a dislodged stabiliser wire rather than the switch. Lift the keycap and reseat it.

Stuck Key or Runaway Repeat? Telling Them Apart

These two faults feel identical and have completely different fixes. The readouts above separate them.

Symptom	What this page shows	Cause and fix
One letter fills the screen	Key appears in the held list and stays there	Physically stuck switch. Pull the keycap and clear the debris.
Everything types in capitals	ShiftLeft or ShiftRight in the held list	Stuck Shift. Press and release it firmly several times; clean underneath.
Letters trigger shortcuts instead of typing	ControlLeft or ControlRight in the held list	Stuck Ctrl. Same fix — and check Sticky Keys is off.
Characters repeat occasionally, not constantly	Repeat counter climbing, held list empty	Runaway repeat or chatter. Lower the auto-repeat rate; test for chatter.
Nothing is stuck here but the fault is real elsewhere	Held list empty, no repeats	Software — a remapping tool, macro layer, KVM or remote session.
A key sticks only sometimes	Appears in the held list intermittently	Sticky residue from a spill, or a failing stem. Clean; then replace.

There is one more possibility worth naming, because it is common and has nothing to do with hardware: Sticky Keys. This accessibility feature deliberately latches modifiers so they stay active after you release them, which is exactly what a stuck modifier looks like. It is switched on by pressing Shift five times in a row, so it gets enabled accidentally all the time — often by a game. If a modifier appears stuck and the physical key feels normal, check Sticky Keys before opening the keyboard.

Fixing a Physically Stuck Key

Once you have confirmed the fault is the switch rather than software, the repair depends on the keyboard type. Work in this order.

Work the key. Press and release it firmly twenty or thirty times while watching the held list. A key held by loose debris often frees itself, and this costs nothing.
Pull the keycap and look. On a mechanical keyboard a keycap puller lifts it in a second; on a laptop, lever gently from one corner with a plastic tool. Nine times in ten you will see the problem — a crumb, a hair, or dried liquid around the stem.
Compressed air, then isopropyl alcohol. Air first, from two or three angles. If the key still sticks, a few drops of 99% IPA into the switch and fifty presses to work it through will dissolve sugary residue. Let it dry completely before powering on.
Check the stem and the stabilisers. A cracked keycap stem binds against the switch housing and feels stuck even though the switch is fine — the fix is a new keycap, not a new switch. On wide keys, a dislodged stabiliser wire does the same.
Replace the switch. On a hot-swap board this is a two-minute job with a puller and no soldering. On a soldered board it needs desoldering. On a laptop the switch is not separable, and a persistent stick usually means a keyboard assembly replacement.
If it followed a spill, act now. Sugary liquids corrode traces over days. A key that sticks intermittently after a spill will usually fail permanently if left, so clean it while it is still intermittent.

A temporary workaround if you need the machine working immediately and the stuck key is one you can live without: remapping tools on every platform can disable a single key outright. That stops a stuck Ctrl from making the computer unusable while you wait for parts. It is a stopgap, not a repair — and if the stuck key is a modifier you actually use, the other one on the opposite side of the keyboard can cover for it in the meantime.

Frequently Asked Questions

How do I test for a stuck key?

Open this page, click once to give it focus, then take your hands off the keyboard. Every key the computer thinks is held down is listed with a live timer. On a healthy keyboard the list is empty the moment you let go, so anything remaining is stuck.

Why does my keyboard keep repeating one letter?

Either the switch is physically held closed — debris, a cracked keycap stem or dried liquid — or the controller has lost the release event. Check the held-key list here: if the key appears while you are not touching it, it is physically stuck.

Why is everything I type in capital letters?

A stuck Shift, or Sticky Keys. Check the modifier warning above: if a Shift key shows as held with your hands off the keyboard, it is stuck. If it does not, Sticky Keys is latching it — that feature is toggled by pressing Shift five times, so it often gets enabled by accident.

Why do my letters trigger shortcuts instead of typing?

A stuck Ctrl or Command key. Every letter becomes a shortcut, so S tries to save and A selects everything. This page shows it directly in the held list, which saves a lot of guesswork.

What is the difference between a stuck key and key chatter?

A stuck key sends one keydown and never releases, so a character repeats endlessly. Chatter is a switch registering two presses for one push, so you get doubled letters. This page catches the first; the double typing test measures the second.

Can software cause a stuck key?

Yes. Sticky Keys latches modifiers by design. Remapping tools, macro layers, KVM switches and remote-desktop sessions can also lose a keyup and leave a key latched. The tell is that a software-stuck key feels physically normal, and pressing and releasing it usually clears it.

How do I fix a physically stuck key?

Work it thirty times first — loose debris often frees itself. Then pull the keycap and look, since you can usually see the crumb or hair. Compressed air, then a few drops of 99% isopropyl alcohol worked through with the stem, handles the rest. A hot-swap board takes a replacement switch in two minutes.

Why does the list clear when I switch windows?

Because a key held while the window loses focus never delivers its keyup, and it would look permanently stuck. Clearing on focus loss avoids that false alarm — it does mean you should keep this tab in front while testing.

Keyboard Layouts

Hardware Diagnostics

Individual Key Tests

Speed & Sound