Keyboard Tester
Press keys on your real keyboard and watch them light up here. Hold as many keys as you can - the counter shows exactly how many your keyboard registered at the same time.
Keyboard tester & ghosting check
Press keys on your real keyboard - each one lights up here. Hold several at once to test rollover: the counter shows how many keys your keyboard registered at the same time.
Keys down right now: 0 · Max held together: 0 · Total presses: 0
Tip: cheap membranes often drop keys at 3-4 held at once; gaming keyboards advertise 6-key or N-key rollover.
How to read the board
- Tap every key once. A key that stays dark is dead or intermittent; a key that stays lit after release is stuck - both are warranty-relevant faults on a new board.
- Hold keys together. Two, three, four - the "max held" counter is your board's real rollover. Membrane keyboards commonly stop at 2-3; a gaming board should hold 6 or more.
- Test your actual problem combos. Game movement (W+A+Shift), strafe+jump, whatever you use - if your real combination drops a key here, no in-game setting will fix it.
| Board type | Typical max held | What it means for you |
|---|---|---|
| Budget membrane | 2-4 keys | Multi-key game combos may drop inputs |
| Office membrane | 2-3 keys | Typing only - perfectly fine |
| Mechanical (6KRO) | 6 keys | Covers nearly every game combo |
| Mechanical (NKRO) | All keys | Every key tracks independently |
The counter reads standard browser keyboard events, which report the same scan codes games see on the web - it cannot measure USB polling details, but for finding dead keys and rollover limits it is exact.
Frequently asked questions
What does a keyboard tester show?
Every key you press lights up on an on-screen layout, so dead keys, stuck keys and mis-firing keys are visible in seconds. It also counts how many keys you held at once - the number keyboards advertise as rollover.
What is key rollover (6-key vs N-key)?
Rollover is how many simultaneously held keys the keyboard reports correctly. Membrane boards often drop keys beyond 3-4 held together; gaming boards advertise 6-key rollover or N-key (NKRO), meaning every key tracks independently.
Why do some key combinations never register?
Cheap boards route keys through a shared wire matrix; certain combinations collide electrically and drop one key - ghosting. If a specific three-key combo always loses a key on this test, that is the board matrix, not your fingers.
Can I test a laptop keyboard?
Yes - the same events fire. Laptop keyboards routinely manage only 2-3 simultaneous keys, which is normal for the form factor rather than a fault.
A key lights up but types the wrong character - is the board broken?
The hardware is fine: the scan code is correct but the OS layout changed. Check the input language setting before blaming the keyboard.