Keyboard Tester — Test Every Key Live
Not sure whether a key is dead, stuck, or ghosting? This free online keyboard tester shows you exactly what your keyboard is telling your computer. Press any key and watch it light up on the screen in real time, with its key code and position readout. It catches stuck keys, finds dead ones, and reveals ghosting on key combinations — all 100% in your browser, no sign-up, nothing uploaded.
Click anywhere on this page, then press keys on your physical keyboard. Each key lights up as you press it.
On a phone or tablet without a physical keyboard you can tap the on-screen keys to see their names — but only a real keyboard gives a true test. Only Tab and Space are intercepted (so the page doesn\'t scroll or lose focus); every other key behaves normally. 100% client-side — nothing is uploaded.
How to use it
- Click anywhere on the page so the tester is listening, then start pressing keys.
- Work through the keyboard row by row — letters, numbers, modifiers, function keys. Each press lights up in blue and adds to your "keys tested" count.
- Watch the readout. It shows the character produced, the physical key code, the legacy keyCode, and whether it\'s a left, right, standard, or numpad key.
- Test combinations. Hold Shift, Ctrl, or Alt and press other keys together — if one key drops out only in combination, you\'ve found ghosting (see below).
- Check for stuck keys. If a key\'s press signal arrives but no release follows within 3 seconds, it gets a red outline and a warning appears.
Keys your operating system swallows before the browser sees them — most Fn combos, dedicated media keys, and laptop brightness/volume keys — won\'t light up. That\'s normal behavior, not a failure: the tester can only report what actually reaches the browser.
What it expects
Every normal key should light up the moment you press it and go dark the moment you release it. The character in the readout should match what the key types in a text editor with your current language layout active. Left and right modifiers (Shift, Ctrl, Alt) are tracked separately — test both sides, because it\'s common for one side\'s switch to wear out first on heavily used keyboards.
The history log keeps your last 20 presses, newest first, so you can review a sequence — handy when a key works intermittently and you want proof of exactly which presses registered. The counter tells you how many of the on-screen keys you\'ve exercised; a full pass means every switch got at least one press-and-release cycle.
Keyboard problems this catches
- Dead keys — a key that never lights up no matter how firmly you press it. Try another USB port and browser first; if it\'s still dark, the switch (or its solder joint) has failed.
- Stuck keys — red outline plus a warning when a release never arrives. Sometimes it\'s a physically jammed keycap; sometimes the browser just lost focus mid-press, so click back and re-test before concluding anything.
- Ghosting — keys that work alone but vanish in 3+ key combinations. This is a limitation of the keyboard\'s wiring matrix, not damage; keyboards marketed with "n-key rollover" don\'t ghost.
- Double-typing / chatter — one press logging two entries in the history. That\'s a worn switch bouncing, and it shows up clearly as duplicate history chips.
- Wrong characters — the readout\'s "key" doesn\'t match the label. That\'s almost always the OS input language being set to a different layout, not a hardware problem.
Tips for a thorough test
- Test both modifier sides. Gamers wear out left Shift and left Ctrl; typists wear out right Shift. Don\'t skip them.
- Press firmly, then lightly. A dying switch often works with a hard press but misses light taps — that inconsistency is the early warning sign.
- Try your real combos. Test the exact shortcuts you use daily (Ctrl+Shift+T, Alt+Tab-style combos) rather than random keys.
- Unplug extras first. If keys misbehave, disconnect other USB devices — an overloaded hub can starve a keyboard of power and cause phantom misses.
- Retest after cleaning. Crumbs under a keycap are the #1 cause of "stuck" and "dead" keys that aren\'t actually broken.
Frequently asked questions
- How does this online keyboard tester work?
- It listens for your browser's keydown and keyup events. Every time you press a key, the matching key on the on-screen keyboard lights up and the readout shows the key name, code, legacy keyCode, and location (left, right, standard, or numpad). Release the key and the highlight turns off. If a key never lights up, the press never reached your browser.
- A key doesn't light up — is my keyboard broken?
- Not necessarily. First press it a few times firmly, then try a different USB port (or re-pair Bluetooth), and try another browser. Media keys, Fn combinations, and some laptop function keys are intercepted by the operating system before the browser ever sees them — those not lighting up is normal and not a defect. If a regular letter or number key stays dark everywhere, that key's switch is likely dead.
- What does the "stuck key" warning mean?
- If a key sends a press signal but no release signal within 3 seconds, the tester flags it as possibly stuck and outlines it in red. A physically jammed key is one cause — but so is the browser window losing focus mid-press (for example, Alt-Tabbing while holding a key), because the release event goes to another window. Click back on the page and tap the key again to re-test.
- Why don't some key combinations register together?
- That is usually key ghosting, a hardware limitation of the keyboard's internal matrix: most consumer keyboards cannot report certain three-or-more-key combinations, so one press gets dropped. Gaming keyboards advertise "n-key rollover" precisely because they don't have this limit. Try your combo here — if one key drops out only in combination, the keyboard is ghosting, not broken.
- What is the difference between key, code, and keyCode?
- The "key" is the character produced (affected by your language layout — on a French AZERTY keyboard, pressing the top-left letter key reports "q"). The "code" is the physical position of the key ("KeyQ") and never changes with layout, which is why this tester maps highlights by code. "keyCode" is the old numeric system (e.g. 65 for A); it still works but is deprecated, so modern code should use "code" instead.
- Does it work on Mac, laptop, and non-English keyboards?
- Yes. Because highlighting is mapped by physical key position (code), the on-screen US layout still lights up the right physical key on AZERTY, QWERTZ, and other layouts — the character shown in the readout follows your active layout. On Mac, the Command key reports as Meta. On-screen keyboards and phones can tap the visual keys, but a real physical keyboard gives the true test.
- Is anything I type recorded or uploaded?
- No. Everything happens locally in your browser via the standard KeyboardEvent API — key names are shown on screen and never sent anywhere. There is no account, no analytics payload of your keystrokes, and nothing to clear afterward. Avoid typing passwords into any tester as a general habit, though.