Keyboard Tester

How to use the keyboard tester

1. Choose your layout. ANSI is the standard in the US and Canada (wide left Shift, one-row Enter). ISO is used in the UK, Ireland and most of Europe (tall Enter, extra key next to left Shift). If you press that extra key, the tester switches to ISO automatically.
2. Press each key once. Held keys are bright green; tested keys stay tinted green.
3. Keys that don't change colour aren't registering. Try them again, firmly, before deciding they're faulty.
4. Watch for red keys and the Chattering keys count: those keys sent a second press immediately after you released them.

Where your browser allows it (Chrome and Edge), the letters on the keys match your own keyboard layout, such as AZERTY or QWERTZ. Keys are identified by their physical position, so the test works whatever language your keyboard is set to.

Key chatter: when one press types twice

Key chatter is the keyboard version of a mouse that double clicks. A worn, dirty or faulty switch makes contact, bounces and makes contact again, so one press produces "tthe" instead of "the". It's common on mechanical keyboards, especially on frequently used keys like E, Space and Backspace.

The tester flags chatter when a key is pressed again less than the threshold (40 ms by default) after it was released. People can't tap the same key that fast on purpose, so these are almost always switch faults. If you're a very fast typist and see flags on deliberate double letters, lower the threshold a little.

How to fix key chatter

1. Clean the switch. Remove the keycap and blow compressed air into the switch, then press the key rapidly 50–100 times to work the contacts.
2. Raise the debounce time in your keyboard's software or firmware (many gaming and custom keyboards allow this). It filters out chatter at the cost of a few milliseconds.
3. Swap the switch. Hot-swappable keyboards let you pull the switch and fit a new one in a minute. On soldered boards it needs desoldering.
4. Use the warranty. Chatter is a recognised defect. A screenshot of this tester is useful evidence.

Rollover and ghosting

Key rollover is how many keys a keyboard can register at once. Hold down several keys together and watch the Most keys at once number: many office keyboards stop at 2–6 keys in some combinations, while gaming keyboards often advertise "N-key rollover", meaning every key can be pressed at once. Ghosting is when the keyboard registers a key you didn't press, and blocking is when it ignores one you did; both happen on cheaper keyboards when certain combinations are held together.

To test your gaming keys, hold the combinations you actually use, such as W + A + Shift + Space, and check every key lights up. Bear in mind that your operating system and browser also intercept some combinations, so a missing key in a complex combination isn't always the keyboard's fault.

Keys browsers can't always see

• Fn is handled inside the keyboard itself and is never sent to the computer.
• The Windows key, Alt + Tab and Esc may be taken by the operating system or browser. In Chrome and Edge, Full-screen capture lets the tester receive them; hold Esc to leave full screen.
• Print Screen often only reports when it's released. The tester counts that as a press.
• Media and extra keys (volume, F13–F24, macro keys) appear under "Keys outside this layout" if your browser receives them.

Frequently asked questions

A key doesn't light up. Is my keyboard broken?

Check it in another program (a text editor) first. If it doesn't work anywhere, the switch or its connection may be faulty. Also check for a "game mode" or Win-lock switch on gaming keyboards, which disables some keys.

Does this work with laptop keyboards?

Yes. Choose the layout closest to yours; keys your laptop doesn't have (like the numpad) can simply be left untested.

Does it work with Mac keyboards?

Yes. Command shows up as the Win key position and Option as Alt. macOS doesn't report key releases while Command is held, so the tester clears held keys when you release Command.

Can it measure my keyboard's polling rate or latency?

Not accurately. Browsers add their own timing, so any number would be misleading. The press durations in the log are useful for spotting sticky keys, though.

Is anything I type recorded?

No. Key presses are shown on this page only and never leave your browser.