Keyboard test
Press every key and watch it light up. Finds dead keys, stuck keys and rollover limits. Nothing is recorded or sent anywhere.
Keyboard shortcuts are disabled while the test runs so your keys reach this page instead of your browser. Press Escape twice or click Stop to finish.
The Fn key is handled inside your keyboard firmware and never reaches any website. Ctrl+Alt+Del, Cmd+Tab and the Windows key are captured by your operating system first, so those are marked as unreachable rather than failed.
How to read the results
Every key starts grey. Pressing a key turns it blue while it is held, and green once it has registered at least once. A key that stays grey after you have pressed it firmly a few times is not reaching your browser.
The rollover peak counts the most keys reported at the same time. It matters for gaming, where you might hold three movement keys plus a modifier, and it is the number cheap keyboards fail on.
What a failed key usually means
One key is completely dead
On a mechanical keyboard this is a failed switch. It is a cheap fix if your board is hot swappable, and a soldering job if it is not. On a membrane keyboard the contact pad under that key has worn through and the practical fix is a new keyboard.
A key repeats or sticks
If a key shows as held when you are not touching it, either debris is holding the switch closed or the switch has failed shorted. Pull the keycap and check before replacing anything.
A whole row or block fails
That points at the controller or ribbon cable rather than individual switches, which is common after liquid damage. On a laptop the ribbon connector is worth reseating.
Keys work individually but not in combination
This is a rollover limit, not a fault. Your keyboard is working as designed, it just cannot report that many simultaneous presses.
Before you conclude the keyboard is broken
Try it on a different USB port, and on a different computer if you have one. Check whether the key works in a plain text editor. If a key produces the wrong character rather than nothing, that is a layout mismatch in your OS settings, not a hardware fault, and this test will show the correct physical key lighting up.
Common questions
Why does my Fn key not register?
The Fn key is handled inside your keyboard firmware and never produces a browser event. No website can test it. The same is true of most media keys on laptops, which are translated into other keycodes before they reach the operating system.
Why can I not test Ctrl+Alt+Del or the Windows key?
Your operating system intercepts those combinations before any application sees them. This is a deliberate security measure. The individual Ctrl and Alt keys still register on their own.
What is n-key rollover and what should my peak be?
Rollover is how many keys your keyboard can report at the same time. Hold down as many keys as you can and watch the rollover peak. Membrane keyboards typically stop somewhere between 3 and 6. Mechanical keyboards with full n-key rollover will keep counting past 10.
A key registers sometimes but not always. Is that a dead key?
That is usually debris under the keycap or a failing switch rather than a fully dead key. Press it 20 times and count the misses. On a mechanical keyboard, pulling the keycap and using compressed air fixes it more often than not. On a membrane keyboard the contact pad is likely worn.
Does this send my keystrokes anywhere?
No. The test runs entirely in your browser. Nothing is transmitted, logged or stored, and the page has no server to send keystrokes to.
Troubleshooting guides
Test your other hardware
Most hardware faults travel in pairs. If one device is misbehaving, check the rest.