Keyboard Test
A dead or unreliable key is easy to miss until you actually need it, and 'how many keys can I hold at once' is close to impossible to judge by feel. This free tool lights up an on-screen keyboard diagram in real time as you press, keeps a marker on every key you've already confirmed, and counts how many you're holding down simultaneously, so you can sweep the whole board and find your keyboard's actual rollover ceiling in a couple of minutes. It runs entirely in your browser: no keystrokes are ever recorded, logged, or sent anywhere.
Keys held right now: 0
0 of 87 keys tested
Click here, or press Tab to focus, then start pressing keys
Needs a physical keyboard — on-screen touch keyboards won't register here.
How it works
- Click or Tap the Diagram to Focus It. The diagram only listens for key presses once it's focused, so a stray press while you're scrolling the page never gets captured by accident.
- Check the Layout Matches Your Keyboard. The diagram defaults to ANSI (US-shape) or ISO (EU-shape) based on your language, but you can switch either way; look at your Enter key and the key next to your left Shift to tell which one your hardware actually is.
- Press Every Key You Want to Check. Work across the board methodically, row by row. Each key lights up bright the instant it registers.
- Watch It Dim to a 'Tested' Mark on Release. Once you let go, the key stays visibly marked instead of resetting, so you can see at a glance which keys you've already confirmed and which ones you haven't gotten to yet.
- Hold Several Keys at Once to Check Rollover. Try a real combo, like holding a diagonal (W+A) plus Shift plus Space, and watch the live counter. If it stops climbing while you're still pressing more keys, you've found your keyboard's rollover ceiling.
- Reset to Sweep Again. Reset clears every tested mark without affecting a key you're still physically holding, so you can run a clean second pass any time.
How to Read the Diagram
Every key has three states: neutral (not pressed yet this session), bright (physically held down right now), and marked (pressed and released at least once). The goal is to turn every key you care about into a marked one, so a glance at the board tells you what's left to check.
What Key Rollover (and Ghosting) Actually Means
Every keyboard has a limit on how many keys it can correctly report at the exact same time. That limit is called its rollover, and it's usually described as N-key rollover, or NKRO, when a keyboard can report every key on the board simultaneously with no limit at all.
- 2-key rollover: only 2 keys register reliably at once; common on very basic keyboards.
- 6-key rollover (6KRO): up to 6 non-modifier keys plus modifiers at once. This is the USB standard 'boot protocol' limit, and it's the ceiling on a large share of ordinary keyboards.
- N-key rollover (NKRO): every key can be held at once with no practical limit, using a USB report format built for it rather than the 6-key boot protocol.
Ghosting is a related but different problem: on a keyboard matrix without a diode at every key, certain 3-key combinations can make the controller register a key you never pressed, or silently drop one you did. Some keyboards handle this safely by refusing extra input once a risky combination is detected (sometimes called jamming) rather than reporting a wrong key; either way, it shows up here as a key that won't light up alongside certain others.
Why Rollover Differs Between Keyboards
Rollover isn't about mechanical vs. membrane vs. optical switches directly, it's about whether the keyboard has a diode at every key and whether its firmware reports over USB using the full-NKRO format or the simpler 6-key boot format.
- Membrane and cheap laptop keyboards commonly skip per-key diodes to cut cost, so they're usually limited to somewhere around 2- to 6-key rollover.
- Mechanical keyboards marketed for gaming very often wire a diode into every switch and report using a full NKRO format, so they can be genuinely limitless.
- Optical and Hall-effect switches don't create rollover on their own either; they're a different way of detecting a keypress, but they're commonly bundled with full per-key wiring and NKRO firmware as a companion feature, which is why they're associated with high rollover in practice.
- Some keyboards need a driver, a key combo, or a software toggle to switch from the default 6KRO boot mode into their full NKRO mode; check your keyboard's manual if this test reports a lower ceiling than the box advertised.
ANSI vs. ISO: Which One Is My Keyboard?
These are the two common physical shapes for a Western keyboard layout, and they're a hardware-shape question, not a language one.
- ANSI (US shape): a single flat, wide Enter key, and no extra key between left Shift and Z.
- ISO (used across most of Europe, including Romania): a taller, narrower Enter key that hangs down into the row below, plus one extra key immediately to the right of left Shift.
Picking the 'wrong' one only changes which shape the diagram draws; every key still tests correctly by its physical code either way, since the two layouts share the same underlying key positions apart from that Enter/Shift area.
Why Didn't a Key Light Up? Troubleshooting
Before assuming a key is faulty, rule out the keys that were never going to reach this page in the first place.
- Ctrl+Alt+Delete on Windows is intercepted at the operating-system level for security reasons; no application, including a browser, can ever see it.
- Fn on most laptops isn't a normal key at all: the keyboard's own firmware usually remaps it before it ever becomes a USB signal, so it commonly never reaches any web page, this test included.
- Many browser and OS shortcuts are reserved regardless of what a page does, commonly things like closing or switching tabs, Mission Control or the app switcher, and screenshot shortcuts; a key not lighting up there is expected, not a hardware fault.
- Media keys, volume, and brightness keys are sometimes handled entirely by the OS and never generate a standard key event a webpage can read.
If you've ruled those out and a normal letter, number, or modifier key genuinely never lights up no matter how you press it, that's a real signal worth investigating: check for debris under a mechanical switch, a low battery or dropped connection on a wireless board, or a remapping tool running in the background.
Per-OS and Browser Notes
A handful of details are worth knowing before you test.
- OS- and browser-reserved shortcuts always win regardless of which browser you're using (see the troubleshooting section above for specifics).
- On-screen or virtual touch keyboards (phones, tablets) don't produce the same physical key codes a hardware keyboard does, so this test is built for a physical keyboard, wired or wireless.
- This test reads the physical key position (its code), which is independent of your OS's input language, so it works correctly no matter what language your system is set to type in.
Frequently asked questions
Does this record or log what I type?
No. Nothing is recorded, logged, or sent anywhere. The test only tracks which physical keys have been pressed during this page visit, entirely inside your browser, purely to light them up on screen; it never reads or stores what those keys would actually type.
Why didn't a key light up?
First check whether it's an OS- or browser-reserved combination (Ctrl+Alt+Delete, tab-switching shortcuts, media keys, laptop Fn) — those are commonly intercepted before any webpage ever sees them, this test included. If a normal letter, number, or modifier key never lights up despite that, it may genuinely be faulty; check for debris, a battery or connection issue on wireless keyboards, or a background remapping tool.
Is a low rollover count normal, or is my keyboard broken?
Normal, in most cases. Rollover depends on whether a keyboard has a diode at every key and how its firmware reports over USB, and plenty of ordinary membrane and laptop keyboards cap out around 2 to 6 simultaneous keys by design. That's rarely noticeable for typing, since typing rarely holds more than two or three keys down at once.
What's the difference between rollover and ghosting?
Rollover is how many keys a keyboard can correctly report at once. Ghosting is a specific failure mode on keyboards without a diode at every key, where certain 3-key combinations can make the controller report a key that wasn't pressed, or drop one that was, because of how the internal grid is wired.
Why does the on-screen diagram look different from my physical keyboard?
You're likely looking at the other physical layout. ANSI (common in the US) has a flat, wide Enter key and nothing between left Shift and Z; ISO (common across Europe, including Romania) has a taller Enter key and one extra key next to left Shift. Toggle the layout switch above the diagram to match your hardware; it only changes the shape drawn, every key still tests correctly either way.
Does this work with a Bluetooth or wireless keyboard?
Yes, as long as it's connected and typing normally, a wireless keyboard behaves the same as a wired one to your browser. If keys feel inconsistent, check the battery level and connection first before assuming a hardware fault.
Does my keyboard's language or input layout affect the test?
No. The test reads each key's physical position rather than the character it types, so it works correctly no matter what language or input layout your system is set to.
Can I test a laptop's built-in keyboard the same way as an external one?
Yes, both work the same way here. Built-in laptop keyboards more often land on the lower end of the rollover range than dedicated mechanical keyboards do, which is normal for that hardware class rather than a sign of a problem.
How many simultaneous keys should a normal keyboard support?
There's no single right answer, it depends on the keyboard class. Budget membrane and many laptop keyboards commonly land around 2 to 6 keys, while mechanical keyboards built for gaming often advertise full N-key rollover with no practical limit. Either can be entirely normal for what it's designed for.
Every part of this test runs locally in your browser; no keystrokes, key combinations, or anything else about what you type are ever recorded, logged, uploaded, or stored anywhere.