About this tool

Hold down multiple keys at once and this tool tracks exactly how many stay registered simultaneously, reporting your keyboard's actual peak rollover — the real-world ceiling on how many keys it can recognize as pressed together — rather than trusting whatever the box claims.

This directly tests for matrix ghosting, the failure mode where a keyboard's row/column scanning circuit can't distinguish a genuine key combination from a phantom key at the intersection of two others. Preset combo buttons (WASD+Shift+Space, QWER+Ctrl, all arrows+Shift) let you stress-test the exact input patterns used in real games, and the tool distinguishes true N-key rollover (NKRO) boards from ones that silently cap out at 2- or 6-key rollover.

Key features

• Live tracking of every currently-held key with a running "max held at once" record
• Preset gaming combo buttons (WASD+Shift+Space, QWER+Ctrl, arrows+Shift) for realistic stress tests
• Full visual keyboard layout so you can see exactly which key in a combo failed to register
• Distinguishes genuine N-key rollover boards from matrix-limited membrane keyboards

Why use it

• Know your keyboard's real rollover limit before it costs you a combo in a live match
• Verify NKRO marketing claims instead of taking them on faith
• Diagnose why a specific key combination fails to register in-game

Why keyboard tester testing matters

Membrane and budget mechanical keyboards often use a matrix circuit that can only recognize a limited number of simultaneous key presses along the same rows and columns — this is what causes "ghosting," where pressing three keys together makes a fourth, unintended key appear to register. Gamers relying on combos like WASD + Shift + Space need to know their rollover limit before it costs them in a real match.

Tips for accurate results

• Press every key on the layout at least once, including modifiers (Shift, Ctrl, Alt, Win) and function keys — some browsers intercept a handful of system shortcuts, so a missed key isn't always a hardware fault.
• Hold down common gaming combinations (WASD+Shift, arrow keys+Ctrl) to find your keyboard's real rollover limit.
• If a key repeats or sticks, check for physical debris under the keycap before assuming switch failure.
• For typing speed, run at least 2–3 attempts — the first is usually slower as you adjust to the prompt text.

Frequently asked questions