DeviceBenchFree online keyboard checker
Keyboard checker that shows every working and dead key
Click the on-screen layout, press keys, and every one that registers lights up its box on a full 104-key board with a counter showing how many times it has fired. The checker reads switch positions rather than letters, so it works on QWERTY, AZERTY and QWERTZ without any setup. A key that never lights is dead, a key that stays lit after release is stuck, and a counter that jumps by two on one clean press is switch chatter — three faults, three signatures, one pass across the board.
- 100% free
- No signup
- 104 keys
- Any layout
- Per-key counter
Your browser shortcuts still work. Press Start, then walk the board.
Nothing pressed yet.
None yet. A count here that runs ahead of your presses is switch chatter.
These never reach a web page and will stay gray however hard you press them: MetaLeft, MetaRight, PrintScreen, F11, F12, along with Fn, Alt+Tab and Cmd combinations. A phone or tablet has no keyboard to test unless you have paired a physical one.
How to check a keyboard online
One pass across the board catches dead switches, stuck keys and chattering contacts.
Click the layout to start the checker
The checker does not grab your keyboard until you click the on-screen layout. That is deliberate: if it captured keys on load, browser shortcuts like Ctrl+W or Cmd+T would stop working. Once the border turns cyan, every physical key you press lights up its matching box and the counter on it goes up by one.
Walk every row, including modifiers and numpad
Go row by row from Escape down to the space bar and across the numpad. Press the left Shift and the right Shift separately — they are different switches and this checker tracks them as different boxes. Same for Ctrl, Alt and Meta on both sides. A sentence only touches thirty or forty keys; a full walk covers all 104.
Read the results off the board
A box that never lit up is a dead switch — the contact no longer closes. A box that stays highlighted after you lift your finger means the key-up event never came back, usually a physically stuck keycap or debris under it. A counter that jumped to 2 on one clean tap is switch chatter, a worn contact bouncing as it closes. Screenshot the board if you need proof for a warranty claim.
Technical specifications
| Layout | 104-key ANSI full-size, including numpad, navigation cluster and both modifier pairs |
|---|---|
| Key detection | KeyboardEvent.code — the physical switch position, not the typed character |
| Modifier tracking | Left and right Shift, Ctrl, Alt and Meta counted as separate switches |
| Auto-repeat handling | Filtered out — a held key counts as one press, not forty |
| Keys the browser cannot see | Fn, most laptop media keys, and OS-reserved combinations like Alt+Tab |
| Per-key counter | Shown on each box, cleared by Reset or a page reload |
| Data stored | None — no keystrokes are assembled into text, saved or transmitted |
| Cost | Free, no signup, no session limit |
Frequently asked questions
How does this keyboard checker work?
It listens for the browser's KeyboardEvent and reads the code property, which identifies the physical switch position rather than the character it types. Each code maps to a box on the 104-key layout; a press lights the box and increments its counter. Because it uses the physical position, the same box lights whether your layout is QWERTY, AZERTY or QWERTZ.
Why does the Fn key not register?
Fn is intercepted inside the keyboard's own controller and never produces a browser event. It changes what other keys send — Fn plus F5 might become a brightness key — but the translation happens before anything reaches the operating system. The same applies to most laptop media keys and layer switches on programmable boards.
Can I use this checker for a new keyboard before I decide to keep it?
That is exactly what it is for. Plug the keyboard in, click the layout, walk every key, and you have a clear answer within a minute. If a key fires twice on one tap, the counter shows it — screenshot the board and you have evidence a shop cannot argue with.
Why does the counter stay at 1 when I hold a key down?
Because the checker filters out auto-repeat. A held key sends dozens of events per second, each flagged as a repeat by the browser. Counting those would make a leaning elbow look like a chattering switch, so only the initial press adds to the counter. If you see 2 on a single deliberate tap, that is a real double — the switch bounced.
Some keys like Alt+Tab do not light up. Is the keyboard broken?
No. A handful of combinations are intercepted by the operating system or the browser before the page ever sees them. Alt+Tab, Cmd+Tab, the Windows key on its own, Ctrl+W and F11 are the usual ones. Every ordinary letter, number, arrow and function key should register. If one of those does nothing, that switch genuinely has a problem.
What is the difference between this checker and the keyboard test?
They use the same tool. This page targets users searching for a keyboard checker specifically, and provides guidance focused on checking whether every switch works. The keyboard test homepage covers the same 104-key layout. If you need to test how many keys your board reports at once, use the key rollover test instead.
About checking a keyboard from the browser
A keyboard checker that runs in a browser has one advantage over a desktop utility: you do not have to install it. Plug in the keyboard you want to test, open this page, click the layout and start pressing. That matters most when the keyboard is not yours yet — a second-hand board, a store return, or a freshly built custom — because you get a verdict before you commit to drivers, firmware tools or a twenty-minute download on hotel Wi-Fi.
What makes this checker reliable is the field it reads. Every keystroke carries two identifiers: KeyboardEvent.key, which is the character after your operating system has applied layout rules, dead keys and modifiers, and KeyboardEvent.code, which is the physical position of the switch — the key to the right of the left Shift is always KeyZ, whether it types z, y or w. This page draws its board from code, so it needs no knowledge of your language and never confuses a layout difference for a broken switch. If several keys work fine alone but drop out when you hold them together, the switches are healthy and the limit is the keyboard’s wiring matrix — the key rollover test measures that ceiling separately.
If every key lights but presses feel slow, the issue is latency rather than a dead switch. The keyboard latency test times the gap between a keypress and the frame that reacts to it. And if what you actually want to measure is how fast you type rather than whether every switch works, the typing speed test scores words per minute and accuracy over a timed passage.
What happens to the keys you press
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type, paste or open is uploaded, logged or kept, which is also why the tools carry on working after you disconnect from the network.
Each keystroke lights a box and adds one to a counter. Nothing is assembled into text, nothing is written to storage and nothing leaves the tab. Reloading the page loses your counts because there is nowhere they could have been kept.