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Keyboard tester: test every key online
Quick answer: click the keyboard below and press every key. Each key lights up while held and stays marked once it registers, so a key that never lights up is dead or not reaching your computer, and a key that fires twice in one press is chattering. Pick full-size, TKL, 75%, 65% or 60% to match your board.
By WFH Lounge editorial team · Updated
Click here (or Tab to it) and start typing.
Full-size (100%)
On a phone, plug in or pair a keyboard; the on-screen phone keyboard doesn’t report physical keys.
Keys tested
0 / 104
0% of this layout
Last key
—
event.key / event.code
Most keys held at once
0
rollover check
Possible chatter
0
0 presses, none under 40 ms
Event log
Key events appear here as you type.
Chatter threshold
Held-key auto-repeat is ignored. If a deliberate fast double-tap gets flagged, lower the threshold.
Keys not on this layout
None yet. Media keys, F13+ or an ISO key show up here if your keyboard sends them.
How to test a keyboard
- Pick your layout (full-size, TKL, 75%, 65% or 60%) and Windows or Mac modifiers. Not sure which you have? Count your keys and check the size table below.
- Click the keyboard or Tab to it. While it has focus it captures keys like Tab, Space, arrows and F-keys so the page doesn’t scroll. Press Esc (or click anywhere else) to release it.
- Press every key once. Watch the “keys tested” counter climb. Keys left unmarked at the end are the ones to investigate.
- Check for chatter: type normally for a minute. A key outlined in amber fired twice faster than the threshold you set.
- Check for ghosting: hold the combinations you actually use (WASD plus Shift and Space in games, your editor shortcuts) and confirm every held key lights up.
Keyboard sizes and key counts
Typical US (ANSI) key counts, per Keychron’s layout guide. Brands add or drop a key or two (a knob, an extra column), and ISO boards used in the UK and Europe differ slightly, so treat these as the standard layout rather than a rule for every model. The tester’s on-screen layouts follow these counts, with Fn included as a physical key.
| Size | Also called | Typical keys | What it drops vs full-size | Good for |
|---|---|---|---|---|
| 100% | Full-size | 104 | Nothing: function row, navigation cluster, arrows and number pad | Spreadsheets, data entry, anyone who types numbers all day |
| 96% | Compact full-size, 1800 | 100 | Squeezes the navigation cluster in beside the number pad; keeps the numpad | A number pad on a narrower desk |
| 80% | Tenkeyless (TKL) | 87 | The number pad | Most office work, with more room for the mouse |
| 75% | Compact tenkeyless | 84 | Number pad; navigation keys move into a single right-hand column | Laptop-like layout that still has F-keys and arrows |
| 65% | Compact | 68 | Number pad and function row (F-keys move to an Fn layer) | Writers and coders who want arrows but not F-keys |
| 60% | Mini | 61 | Number pad, function row, navigation keys and dedicated arrows | Small desks and travel; arrows live on an Fn layer |
What keyboard ghosting is, and how to fix it
Ghosting (often really blocking) is when a keyboard can’t report a particular combination of keys held at the same time: one of the held keys simply never registers, or on older designs a key you didn’t press appears. It happens because cheaper keyboards wire their keys in a shared grid, and some combinations of grid positions can’t be told apart. Microsoft’s ghosting demo notes that even the simplest design fails on thousands of three-key combinations, a small share of the total, which is why most people never notice until a game or a shortcut needs one.
How to check: hold the exact keys you use together and look at the “most keys held at once” counter. A board marketed as “N-key rollover” (NKRO) should light every key you hold. A board that stops at a fixed number, or that drops one specific combination, is blocking.
What helps:
- Check the manual or the maker’s software for an NKRO or “gaming” mode; some boards ship with it off.
- If the keyboard is wireless, run the same test wired (or on its USB receiver) and compare the results.
- Remap the clashing shortcut to keys that don’t share the conflict.
- If you need many keys at once for games or music software, replace it with a board that states N-key or anti-ghosting support.
What key chatter is, and how to fix it
Chatter is one press registering as two or more: “hello” arrives as “helllo”. Mechanical switch contacts bounce for a moment as they close, and the keyboard’s firmware ignores that bounce for a short debounce window (QMK firmware, used on many enthusiast boards, defaults to 5 ms). When a switch is worn, dirty or damaged it can bounce for longer than the window, and the extra contact gets reported as a second press.
How to check: type normally and watch for keys outlined in amber, or the “possible chatter” counter. A real chattering key usually repeats the problem; a single flag after a deliberate fast double-tap is not chatter, so lower the threshold and try again.
What helps:
- Unplug the keyboard, pull the keycap and blow out dust or crumbs under it.
- If your keyboard’s software or firmware has a debounce setting, raise it a few milliseconds.
- On a hot-swappable board, swap the switch for a spare. Otherwise check the warranty: chatter on a new keyboard is a defect.
What a browser keyboard test can’t see
- Fn. Handled inside the keyboard on most models, so it never sends its own code. It is drawn dashed and left out of the count.
- System shortcuts. Alt+Tab, Cmd+Tab, Win+L, Ctrl+Alt+Del and similar are taken by the operating system first. The W3C keyboard-lock draft notes these keys are not normally made available to web pages, and that Ctrl+Alt+Del can’t be overridden at all.
- Some media, brightness and macro keys are handled by the OS or the maker’s app. If they send a standard code they appear under “keys not on this layout”.
- Mac quirks. macOS reports Caps Lock as a toggle and holds back other keys’ release events while Cmd is down; the tester compensates so keys don’t stay lit.
- Latency and polling rate. Browsers don’t expose either, so this page doesn’t claim to measure them. Hold times in the log are browser timings, useful for spotting chatter, not a latency test.
How this keyboard tester works
Every key is matched by event.code, which identifies the physical key position regardless of your language layout (on AZERTY the key in the Q position still reports KeyQ), and the log shows event.key next to it, which is the character that key produces. A key counts as tested the first time its keydown arrives. Chatter is flagged when the same key sends a new (non-repeat) keydown within your threshold of its previous one; held-key auto-repeat is excluded. The rollover figure is the largest number of keys the browser saw held down at the same moment. Everything runs in your browser and nothing you type is stored or sent.
Keyboard failed the test?
Dead keys and chatter that cleaning doesn’t fix usually mean a replacement. These come from our ranked keyboard picks, scored on manufacturer specs and owner feedback.
Not sure what size to get? Try the keyboard finder, or set your desk to elbow height with the desk height calculator.
Keyboard tester FAQ
How do I test my keyboard online?
Click the on-screen keyboard on this page and press every key once. Each key lights up while you hold it and stays marked after it registers, and the counter shows how many of the layout's keys you have tested. Any key that never lights up is not reaching your computer.
Why doesn't my Fn key show up in a keyboard tester?
On most keyboards Fn is handled inside the keyboard itself: it changes what the other keys send rather than sending a code of its own, so no web page can see it. Test Fn by pressing Fn plus a key that has a second function, such as a media or F-key, and checking that the second function works.
What is keyboard chatter?
Chatter is when one press registers as two or more, so you get doubled letters. It comes from switch contacts bouncing longer than the keyboard's debounce filter expects. This tester flags a key that fires again within a threshold you choose (40 ms by default).
How do I check my keyboard for ghosting?
Hold down several keys at once, for example the keys you press together in a game or a shortcut, and watch the "most keys held at once" counter and the on-screen keys. If a key you are holding does not light up, your keyboard blocked that combination.
Can a browser keyboard test check every key?
No. The operating system takes some shortcuts before the browser sees them, such as Alt+Tab, Cmd+Tab, Win+L and Ctrl+Alt+Del, and some media or brightness keys never reach the page. Keys that do reach the browser are reported reliably.
How many keys does a TKL keyboard have?
A standard US (ANSI) tenkeyless keyboard has 87 keys, per Keychron's layout guide. A full-size board has 104, a 75% board 84, a 65% board 68 and a 60% board 61, though individual models vary by a few keys.
Sources
- Keychron: Keyboard Size & Layout Buying Guide — Key counts per layout size (104 / 100 / 87 / 84 / 68 / 61).
- MDN Web Docs: KeyboardEvent: code property — Why the tester maps keys by physical position (event.code) rather than the character (event.key).
- QMK Firmware documentation: Contact bounce and debounce — What switch bounce is and QMK's 5 ms default debounce time.
- Microsoft Applied Sciences: Keyboard Ghosting Interactive Demonstration — Ghosting: some multi-key combinations fail to register on simpler keyboard designs.
- W3C Web Incubator Community Group: Keyboard Lock specification — System shortcuts such as Alt+Tab and Cmd+Tab are not normally passed to web pages; Ctrl+Alt+Del cannot be overridden.
Last checked: . WFH Lounge recommendations are researched from manufacturer specs and owner feedback, not hands-on testing.