KEYBOARD ROLLOVER TEST

Hold as many keys as you can at once — the maximum simultaneous count is your rollover (N KRO).

Press as many keys as possible at once — the max count is your rollover.

Num Lock Caps Lock Scroll Lock

Esc

F10

F11

F12

Backspace

Tab

{[

}]

Caps Lock

Enter

Shift

Ctrl

Win

Alt

Win

Ctrl

PrtSc

ScrLk

Pause

Ins

Home

PgUp

Del

End

PgDn

↑

←

↓

→

Num

Enter

Some OS key combos are captured by the system — that is expected, not a bug.

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About this test

Rollover is how many keys your keyboard can register at the same time: 6KRO means any six keys work together, NKRO (N-Key Rollover) means all of them do. The tester counts distinct keys currently held and shows the result as "Rollover: N KRO".

How it works: keyboards scan a row-column matrix. When several keys on shared rows or columns are held at once, cheap circuits cannot tell where the current flows — keys ghost or drop out. Diode isolation or per-key scanning is what makes full NKRO possible.

How to test: press as many keys as you can at once (a palm works, or grab a friend), or start with a gaming cluster like WASD + Space + Shift and keep adding keys. Watch which keycaps light and which go dark. Note that OS-level shortcuts are intercepted by the system and simply never reach the browser.

Frequently asked questions

How much rollover do I need?

6KRO is plenty for everyday typing. For gaming, aim for 10KRO or better so combos like WASD + Shift + Space never drop a key. For rhythm games or two players on one keyboard, go straight to full NKRO.

Why do some key combinations never register?

Combos that involve OS shortcuts — most combos with Win or Cmd, such as Win+L or Cmd+Q — are intercepted by the operating system before the browser sees them. That is a system limitation, not a keyboard fault; try a combo without the system key.

Can a firmware update add rollover to a membrane keyboard?

No. Rollover is determined by the hardware: membrane matrices are typically limited to 2-6 keys. If that limit affects you, the real fix is an NKRO-capable mechanical keyboard.