Test keyboard combinations and rollover

Hold as many keys as you like and the counter shows how many arrive at once, which makes this page an anti ghosting keyboard test, an NKRO (n-key rollover) test and a 6KRO test in one. It also works as a multiple key press test for any key combination you use. The first preset is a ready-made WASD test for games. Press and hold keys one by one to find out how many keys can be pressed at once on your keyboard, and which combinations go missing when you cannot press multiple keys together.

How the ghosting and rollover test works

1. Choose a preset. WASD + Shift + Space covers most game movement. Home row holds eight letters at once. You can also pick your own keys.
2. Hold all highlighted keys down together. Press them one by one and keep them down.
3. Look at Best together. It shows the largest number of your chosen keys that the browser saw held at the same moment.
4. Any key in Missing did not arrive while the others were held. That is a sign of key blocking on your keyboard.

The test only counts keys that are held at the same time. Pressing the keys one after another does not raise the score.

Ghosting, blocking and rollover explained

Key rollover is how many keys a keyboard can report at once. A keyboard with 6-key rollover (6KRO) reports six normal keys plus modifiers such as Shift and Ctrl. N-key rollover (NKRO) means every key can be reported independently.

Blocking (also called jamming) happens when you press a combination the keyboard cannot report: one or more keys simply do not register. This is what most people notice in games, for example when you cannot jump while running diagonally.

Ghosting is the rarer opposite: the keyboard reports a key you did not press. Cheap membrane keyboards share wires between keys in a grid, and some three-key combinations make a fourth key look pressed. Modern keyboards usually block such combinations instead of sending a ghost key. If a key you did not press shows up under Extra signals, you have found real ghosting.

What your result means

Results describe the whole chain: keyboard, connection, operating system and browser. Some laptops limit combinations in certain areas of the keyboard, and a few gaming keyboards switch to 6KRO in their BIOS or compatibility mode. If a combination fails, try another USB port, check the keyboard’s software for an NKRO setting and test again.

Tips for gamers

• Test the exact keys you use: pick them with Pick keys and hold them the way you play.
• Many games combine movement with Shift, Ctrl or Space. These modifiers are part of the WASD preset for that reason.
• A Windows shortcut can steal a combination before the browser sees it. If Shift or Ctrl behaves oddly, turn off Sticky Keys in the accessibility settings.

For a full key-by-key check use the main keyboard test. To check single keys that type twice, use the chatter test.

Membrane and mechanical keyboards

Most membrane keyboards connect keys in a shared grid to keep costs down. They handle two or three keys well, but certain three-key groups in the same area block each other. Manufacturers often add extra wiring only around WASD and the arrow keys, which is why a cheap “gaming” keyboard can pass the WASD preset and still fail the home row.

Mechanical keyboards usually have a diode on every switch. Diodes stop current from flowing backwards through the grid, which prevents ghosting and allows full N-key rollover. If a mechanical keyboard still blocks combinations, the limit usually comes from the USB report mode rather than the switches.

How to get better combinations

• Look for an NKRO or “game mode” option in the keyboard software or in a key combination listed in the manual.
• Connect wired: some wireless keyboards limit rollover over Bluetooth to save power.
• Move game controls to keys that work together in this test, for example away from blocked letter groups.
• Test again after a firmware update: manufacturers sometimes change the default report mode.

Frequently asked questions