This keyboard tester is a free online tool that checks every key of your keyboard right in your browser — press any key and it lights up instantly, so you can find dead keys, stuck keys, and run a key rollover (NKRO) and ghosting test. It works with laptop, mechanical, wireless and Mac keyboards. Nothing to download, no sign-up, and every keystroke is read locally — nothing you type ever leaves your device.
100% local — keystrokes are read in your browser and never sent anywhere
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Press any key — it lights up below
held down verified working not tested yet — the layout scales to your screen
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Key rollover & ghosting test
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Hold down as many keys as you can (try W+A+Space+Shift plus more letters). If a held key is missing from the list, you've hit your keyboard's rollover limit — that's ghosting territory.
Testing on a phone or tablet?
On-screen keyboards send characters through the field above. Physical keyboards (USB, Bluetooth, laptop) need no field — just press keys anywhere on this page.
How to test your keyboard online
1
Press every key
Go row by row and press each key once. A key flashes green while held and stays dark once verified — the counter tracks your progress toward all keys tested.
2
Watch for stuck keys
A key that stays green after you release it is a stuck key — the switch isn't releasing. A key that never lights up at all is a dead key.
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Run the rollover test
Hold multiple keys at once and watch the live counter. It shows exactly how many simultaneous presses your keyboard registers before ghosting kicks in.
Key rollover & ghosting, explained
Key rollover is how many keys your keyboard can register at the same time. Ghosting is what happens past that limit on cheap keyboard matrices: a pressed key is dropped, or worse, a key you never touched gets reported. Both matter the moment you game (W+A+Shift+Space is already four keys) or type very fast.
Rating
Simultaneous keys
Who it's for
2KRO
2 guaranteed (often more in common combos)
Basic office keyboards. Fine for typing; gaming combos can drop keys.
6KRO
6 + modifiers
Standard for decent keyboards. Covers nearly every real-world game combo.
NKRO
Every key independently
Mechanical & gaming keyboards. Needed for rhythm games, fighting games, heavy macros.
To measure yours: place one hand flat across the letter rows and press down — the "max held at once" counter above records the highest count your keyboard actually delivered. Two things to know: many keyboards are NKRO over a USB cable but drop to 6KRO over Bluetooth, and modifier keys (Shift, Ctrl, Alt) usually don't count against the limit. Testing a game controller instead? Use our gamepad tester — same idea, built for sticks and triggers.
Keyboard tester for laptop keys
Laptop keyboards fail more often than desktop ones — crumbs under flat keycaps, worn membrane contacts, liquid damage — and replacing one means opening the chassis, so it's worth confirming the fault first. This tester treats a built-in laptop keyboard exactly like an external one: every key the operating system can see lights up, on Windows, macOS, Linux and ChromeOS.
The Fn key is invisible by design. It is processed inside the keyboard controller and never reaches the OS — no tester on the internet can see it. Test it indirectly: if Fn+F5 changes your brightness, Fn works.
Media & function keys: on most laptops the F-row defaults to media actions. Hold Fn (or toggle Fn-Lock) to send true F1–F12 — they'll light up in the function row above.
Mac keyboards: Cmd registers as Meta, Option as Alt. Everything else maps one-to-one.
One dead key, rest fine? Pop off the keycap and clean with compressed air before paying for a repair — debris under a single key is the most common cause.
Dead key or stuck key: what to do
A dead key never lights up here no matter how hard you press. Before blaming hardware: test in another browser, unplug other input devices, and on external keyboards try a different USB port or re-pair Bluetooth. If the key is dead everywhere, the switch (mechanical) or membrane dome under it has failed — switches can be replaced individually on hot-swap boards.
A stuck key shows as held (green) when you're not touching it, or repeats characters while typing. That's almost always physical: debris or dried liquid under the keycap. Power off, remove the keycap, clean with isopropyl alcohol, let it dry fully. If your space bar or shift seems to "stick" only in games, it's usually the rollover limit instead — run the ghosting test above to tell the difference. And if you're diagnosing a whole setup, check your microphone and game controller too — both test entirely in the browser.
Keyboard tester FAQ
How do I test if my keyboard keys work?
Press every key one by one on this page. Each key lights up green while held and stays marked once verified, and the counter shows how many keys you've tested. A key that never lights up — even pressed firmly a few times — is a dead key: the switch or matrix under it isn't registering.
How do I test my keyboard for ghosting?
Hold down several keys at once — start with W+A+Space+Shift, then add more letters. The rollover counter shows how many keys are registered simultaneously. If a key you're physically holding doesn't appear (or one you're NOT pressing shows up — that's ghosting), you've hit the rollover limit. Office keyboards register 2–6 keys; NKRO gaming keyboards register all of them.
What is key rollover (NKRO) and how much do I need?
Rollover is how many keys register at the same time: 2KRO guarantees 2, 6KRO guarantees 6, NKRO registers every key independently. Typing needs only 2KRO; 6KRO covers nearly all gaming; NKRO matters for rhythm/fighting games and macros. Many keyboards are NKRO over USB but fall back to 6KRO over Bluetooth.
Why does a key not light up in the tester?
Some keys never reach the browser: Fn is handled inside the keyboard itself, PrintScreen may register only on release, and media keys map to OS actions. If a normal letter or number stays dark, try another browser, then another device — if it's dead everywhere, the switch or membrane contact under it is faulty.
Does this keyboard tester work for laptops and Mac?
Yes — any keyboard your OS recognizes works: built-in laptop keyboards, USB and Bluetooth externals, mechanical and membrane boards, and Macs (Cmd shows as Meta, Option as Alt). The only exception is the laptop Fn key, which is processed in hardware and invisible to every OS and browser.
Is this online keyboard tester safe and private?
Yes. It's a static page listening to standard browser keyboard events locally. Nothing you type is uploaded, logged or stored — no server-side processing, no download, no sign-up. Load the page, go offline, and it keeps working.