Keyboard Tester & Real-Time Key Diagnostics
Press any key to verify it registers, measure hold time in milliseconds, and confirm N-Key Rollover — entirely in your browser, with zero data leaving your device.
- 100% private — nothing leaves your browser
- Instant — no install, no sign-up
- Free forever
Key Event Log
Press a key to see its details here.
Mouse Diagnostic
How This Keyboard Test Online Works
KeyTest Global is a keyboard tester and key tester in one: it listens for native browser keyboard and mouse events and timestamps every action with sub-millisecond precision using the Performance API. Every key you press is validated as physically registered, timed for how long it was held, checked for double-press chatter, and tracked for rollover behavior — all without installing software or sending a single byte to a server.
Understanding Switch Bounce and Debounce Delay
Mechanical and membrane switches don't close a perfectly clean circuit the instant a key is pressed. The metal contacts physically vibrate for a few milliseconds before settling, a phenomenon called switch bounce. Keyboard firmware compensates with a debounce delay — typically 5ms to 20ms — that ignores rapid re-triggers immediately after the first signal. A debounce delay set too high adds perceptible input latency; set too low, it can register a single keystroke as two. A browser cannot see the physical contact, so this tester cannot measure that delay directly. What it can show is the result of weak debounce: its chatter detector flags any key that fires again less than 30ms after being released — faster than a person can press it — and the event log lists each key's hold time.
Membrane Matrix Limitations and Ghosting
Budget membrane keyboards wire keys into a row-column matrix scanned in sequence rather than giving each key its own dedicated circuit. When three or more keys in specific matrix positions are held simultaneously, the controller can misread a fourth 'phantom' key as pressed — a limitation called ghosting. Manufacturers add diodes at each switch to prevent this cross-talk, a technique known as anti-ghosting, but full N-Key Rollover (NKRO) still requires either a fully diode-isolated matrix or a USB protocol capable of reporting more than six simultaneous keys (the classic 6KRO limit of the HID boot protocol). Use the NKRO counter above to find your keyboard's real concurrent key-press ceiling.
Polling Rate and Why It Matters for Mice
Polling rate is how many times per second your mouse reports its position and button state to the operating system, measured in Hertz (Hz). A 125Hz mouse reports every 8ms; a 1000Hz mouse reports every 1ms. Higher polling rates reduce the delay between a physical movement and its on-screen result, which is why competitive gamers favor 1000Hz+ configurations. The mouse diagnostic module above estimates your effective polling rate in real time from the spacing of consecutive pointer events. Browsers that expose high-resolution samples give the most accurate figure; others are limited to your screen's refresh rate and may read close to 60Hz or 144Hz regardless of the mouse.
Optical vs Mechanical Actuation
Traditional mechanical switches register a keystroke through physical metal contact, which is inherently subject to switch bounce and gradual contact degradation. Optical switches instead use an infrared light beam: pressing the key interrupts the beam, and the interruption itself is the signal — there is no physical contact bounce to debounce, which can let firmware use a shorter debounce delay and extends switch lifespan. This tester cannot time the actuation itself, but it can show whether a switch misbehaves: press a key repeatedly and watch the chatter counter. A healthy keyboard of either type should log none; a worn mechanical switch is the most likely to.
How to Test Your Keyboard Online
- 1
Choose your layout
Select 60%, 75%, TKL, or Full to match your physical keyboard's form factor.
- 2
Press every key
Press each key on your keyboard — it turns amber while held, then sticky green once registered.
- 3
Check your results
Review hold times, NKRO, chatter warnings, and any keys that never turned green (stuck or dead).
Frequently Asked Questions
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Type the passage below as quickly and accurately as you can to measure your typing speed in words per minute (WPM).
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Connect a controller and press any button to verify every input works — buttons, triggers, and both joysticks.