Keyboard Test — Free Online Test
Our free Keyboard Test highlights every key you press on an on-screen layout so you can instantly verify that every key on your laptop or external keyboard is working. It supports Windows, macOS, and international layouts and catches stuck keys, dead keys, ghosting, and n-key rollover limits without any install.
How to use the Keyboard Test
- Select your layout (Windows or Mac) at the top of the page.
- Press every key on your keyboard one at a time. Each pressed key turns green.
- To test n-key rollover, hold several keys down at once — the test shows which ones register.
- Watch for keys that do not light up (dead keys) or stay lit after you release them (stuck keys).
How to interpret your results
A healthy keyboard registers every key press exactly once and releases cleanly. Dead keys usually mean debris under the keycap or a damaged switch. Sticky keys point to spilled liquid residue or a failing dome/switch.
Common issues and what they mean
Key does nothing
Remove the keycap and blow compressed air under the switch. If still dead, the switch needs replacement or the keyboard is out of warranty.
Multiple keys register from one press
Called chattering — the switch is failing. Under warranty, request a replacement.
Fn keys do not work
On many laptops, Fn behaviour is controlled by BIOS/UEFI settings or a hotkey (usually Fn+Esc).
When to run this test
- After a liquid spill to confirm which keys survived.
- Before returning a laptop still in warranty.
- When troubleshooting missed keystrokes while typing or gaming.
Diagnosing a laptop keyboard: hardware fault or software?
Before you conclude a key is physically dead, rule out the software layer. A key that produces nothing in this test but works in the BIOS setup screen points at a driver, keyboard-layout or accessibility setting rather than a broken switch. Conversely, a key that fails in both places is almost certainly hardware.
On Windows, three settings cause the majority of false alarms: Filter Keys (which deliberately ignores brief or repeated presses), a mismatched keyboard layout (a US layout on a UK keyboard swaps the quote, hash and backslash keys), and a stale keyboard driver after a feature update. Open Settings, Accessibility, Keyboard and confirm Filter Keys is off, then reinstall the standard PS/2 or HID keyboard driver from Device Manager.
On macOS, check System Settings, Keyboard for Slow Keys and Sticky Keys, and confirm the input source matches the physical layout. On both platforms, an external USB keyboard is the fastest control experiment: if the same key works on a second keyboard, the fault is in the built-in unit.
Ghosting, rollover and why gaming keyboards differ
Membrane keyboards wire their keys into a grid. When you press three keys that share rows and columns, the controller can report a fourth key that you never touched, or fail to report one that you did. That is ghosting, and it is a design limit of the matrix rather than a defect.
Manufacturers work around it with rollover. Two-key rollover guarantees only two simultaneous keys; six-key rollover (6KRO) is the USB HID boot-protocol standard and is what most laptops and office keyboards deliver. N-key rollover (NKRO) adds a diode per key so every switch is read independently, which is why mechanical gaming keyboards can register a dozen simultaneous presses.
Hold six or more keys down in this test and watch the count. If your laptop stops at four or five, that is normal matrix behaviour and not a warranty issue. If a specific pair of keys never works together while other pairs do, note the exact combination — that pattern is useful evidence for support and distinguishes a matrix limit from a failing trace on the keyboard flex cable.
Liquid spills, chattering keys and repair costs
After a spill, run this test on every key rather than only the ones under the splash. Sugary liquids wick along the membrane and cause failures several centimetres from the impact point, often hours or days later. A key that registers twice from one press — chattering — is the classic early symptom of residue or a degraded dome.
Repair economics vary sharply by machine. On most business laptops the keyboard is a serviceable module: Lenovo ThinkPad, Dell Latitude and HP EliteBook keyboards are typically a single part, and a replacement plus fitting usually costs less than a service call. On many thin consumer ultrabooks and MacBooks the keyboard is riveted into the top case, so a single dead key can mean replacing the palm rest, battery and trackpad as one assembly.
Before paying for repair, check whether the machine is still covered. Manufacturer warranties exclude liquid damage, but many retailer and card-issuer protection plans include accidental damage. Document the fault with this test's results page first — a dated list of exactly which keys fail is far more persuasive than a description over the phone.
Frequently asked questions
What is key ghosting?
Ghosting is when a keyboard fails to register a specific combination of simultaneous key presses due to matrix limitations. Gaming keyboards use n-key rollover (NKRO) to eliminate this.
Does the test detect NKRO?
Yes. Hold 6+ keys and the test shows how many the OS actually reports.