Keyboard diagnostic tool

Keyboard Ghosting Test

Use this free keyboard ghosting test to check which keys register when you press several at once. Try common gaming combinations, run a key rollover test, and see the maximum number of simultaneous keys your browser detects. This online NKRO test runs locally without uploading your keystrokes.

Runs locally in this page. Your key presses are not uploaded or saved after refresh.

Keyboard Ghosting & NKRO Tester

Select a mode, then start

● Your key presses stay on this page

Test mode

Try a key combination

Choose a combination, then start the test

WASpace

3 keys in this combination

Click here, press Start Test, then hold every selected key at the same time.

Key display

The diagram uses QWERTY key positions. Labels may differ from the characters on your keyboard. Highlights show your selected keys and the keys you are holding.

`1234567890-=

QWERTYUIOP[]\

ASDFGHJKL;'

Left ShiftZXCVBNM,./Right Shift

Left CtrlLeft AltLeft MetaSpaceRight MetaRight AltRight Ctrl

How to test Keyboard tester Keyboard double typing test

This test needs JavaScript.

Enable JavaScript to test keyboard ghosting and key rollover. You can still read the instructions, terminology, and FAQ below.

Getting reliable results

How to Test Keyboard Ghosting

This ghosting keyboard test only works when keys are held together. Pressing them one after another does not measure simultaneous detection. Keep the test area focused for the whole run.

Focus the test area

Click Start Test, then hold your keys with the test area selected. Pausing or leaving the tab clears the highlighted keys.

Hold a preset key combination

Choose a gaming preset such as W + A + Space, or build a custom combination. Hold every selected key at the same time. Click Finish Test when you are ready to review the result.

Check which keys are detected together

Check whether all selected keys were detected together. If any are missing, try again and make sure you hold the full combination. A missing key does not necessarily mean your keyboard is faulty.

Result statuses

Not started — you have not started a test, or finished before any keys were detected.

Testing — hold the full combination at once. The live count shows keys held now, not keys pressed earlier.

All selected keys detected — every selected key was detected together at least once.

Some keys not detected together — the test did not detect the full combination at once. Confirm whether you held all selected keys before drawing conclusions.

Interrupted — you switched windows or left the tab during the test. Start again to test the full combination. Pause works differently: use Resume to continue the same test, then hold the keys again.

Rollover / NKRO mode shows how many keys are held now and the highest count reached. See how the test works for details.

Terminology

Keyboard Ghosting vs Key Blocking

People often call any multi-key problem “ghosting,” but an extra key appearing is different from a pressed key going missing. Here is how to tell them apart.

Phenomenon	What it means	What this page can show
Ghosting	A key you did not press is detected (a phantom key).	The test lists extra keys detected, so you can check whether you actually pressed them.
Key blocking / masking	A key you did press is not reported while other keys are held.	Missing keys from a preset you confirmed holding are a possible blocking or rollover-limit signal for that combo.
Key rollover limit	The design only guarantees a limited number of simultaneous reports (for example 2KRO or 6KRO).	Max simultaneous counts and failed presets are observations, not a certified KRO rating.
Anti-ghosting	Marketing or design claim that certain multi-key sets should still report correctly.	Useful as context; this page does not verify vendor marketing claims or firmware modes.

Do not treat every missing key as ghosting.

If a preset key never appears, first confirm you held the full combination, then consider matrix limits, OS shortcuts, browser handling, wireless mode, or macros before assuming a dead switch.

Rollover mode

Key Rollover Test: 2KRO, 6KRO & NKRO

Switch the tool to Rollover / NKRO and gradually hold more keys together. This key rollover test shows how many your browser detects at the same time.

Type	Typical meaning
2KRO	Supports two ordinary keys at once. Some larger combinations may also work, depending on which keys you press.
6KRO	Usually supports six ordinary keys at once, with modifier keys such as Shift and Ctrl counted separately.
NKRO / n-key rollover	Design goal is to report all supported keys at once. USB, BIOS, wireless, and compatibility modes can still cap what a host receives.

How to read the maximum

Maximum observed simultaneous keys is taken only from combinations you actually held in this browser session. Seeing 6 ordinary keys does not prove the keyboard is 6KRO. Seeing 10 does not prove true NKRO. Modifier keys are counted separately so a high total is not mistaken for ordinary-key rollover.

Troubleshooting

Why Some Keys Don't Register Together

If some selected keys are missing, check these common causes. Then follow the steps under How to Fix Keyboard Ghosting to narrow down the problem.

Likely cause	What it looks like here	Why the page cannot prove it alone
Incomplete hold	Keys were pressed one after another, or one finger lifted early, so the full combination was never detected together.	Only you know whether every selected key stayed down together. Use the confirmation checkbox only when that is true.
OS or browser shortcut	A chord never appears, or the run jumps to Interrupted when focus leaves the page (Alt+Tab, Ctrl+W, Windows/Command).	The operating system or browser may handle these shortcuts instead. Try a combination of letter keys and Space.
Focus, pause, or auto-repeat	Highlights clear when you leave the test area or pause. Holding a key does not count it more than once.	Cleared highlights do not mean your keyboard stopped working. Select the test area again and hold the keys.
Layout label mismatch	The on-screen label does not match the printed character on a non-QWERTY board.	The diagram uses QWERTY key positions. On other layouts, the labels may differ from the characters printed on your keys.
Rollover cap, wireless, or firmware mode	The same confirmed combo keeps missing the same key; wired vs wireless or “compatibility” mode changes the result.	Try the same combination on another computer and check your keyboard’s manual for connection-specific limits.

Next steps

How to Fix Keyboard Ghosting

There is no universal OS toggle that repairs a physical matrix limit. Work top to bottom: rule out setup issues, then compare what the vendor claims for your model.

1. Retest a safer combination

Use a letter + Space preset or a custom set you can hold without switching windows. Avoid Alt, Win/Command, and browser close/reload chords so the page can actually receive the keys.

2. Check keyboard settings

Turn off Sticky Keys, vendor macros, rapid-trigger profiles, and unusual layers. Keep the test area focused, then run the same preset again before changing hardware.

3. Compare connection modes

If the keyboard supports wired and wireless (or a listed compatibility mode), test the same combination in each mode and note whether the missing key changes.

4. Check vendor KRO / NKRO notes

Read the manufacturer’s 2KRO, 6KRO, NKRO, or anti-ghosting notes for this model. Persistent misses on a confirmed hold are a support or warranty question, not something a browser setting can unlock.

No promised software fix for matrix limits.

If the keyboard only guarantees 2KRO or 6KRO, no online tool can turn it into full NKRO. Do not flash unofficial firmware or open the case before checking warranty terms. For single-key double typing instead of multi-key misses, use the keyboard double typing test.

Test limitations

What an Online Keyboard Test Can Detect

This test checks which keys register when held together. It does not check keyboard lighting or every individual key.

What the results can tell you

Results show which keys your browser detected together and the highest count reached during your test. They cannot prove full NKRO support or pinpoint a hardware fault. System shortcuts, Fn combinations, and some media keys may not reach the page. The test cannot measure USB polling rate or identify your keyboard model. Your results stay on this page and clear when you refresh.

Keyboard Ghosting Test FAQ

What is keyboard ghosting?

Keyboard ghosting means a key you did not press is detected. People also use the term for missing keys when several are held together, but that is called key blocking and may be caused by a rollover limit. This test helps you check which keys register together.

How do I test keyboard ghosting online?

Choose a combination such as W + A + Space, or select your own keys. Click Start Test and hold every selected key at the same time. Click Finish Test to see which keys were detected together. If any are missing, confirm whether you held the full combination before interpreting the result.

What is the difference between ghosting and NKRO?

Ghosting is an extra key appearing when you did not press it. NKRO (n-key rollover) means a keyboard can register all supported keys at once. A keyboard advertised as NKRO may still handle fewer keys in wireless, BIOS, or compatibility modes.

What is a key rollover test?

A key rollover test checks how many keys can be held together while still being reported. Switch this page to Rollover / NKRO mode, hold additional keys, and watch the current and maximum simultaneous counts. Ordinary keys and modifiers are counted separately. The maximum is only for combinations you tried in this browser session.

Why are some keys not registering together?

Common causes include an incomplete simultaneous hold, OS or browser shortcuts that never reach the page, lost focus, wireless or compatibility modes, macros, and matrix or firmware rollover limits. Confirm you held the full set, retry a combination without system shortcuts, and compare another connection mode before assuming a dead switch.

Why did the test say Interrupted?

Interrupted means the run ended because the window lost focus or the tab was hidden while testing was still active. Held-key highlights are cleared so stale keys do not stay lit. Pause only suspends listening — use Resume to continue the same run. After an interrupt, press Start Test again and keep this tab visible for the whole combination.

Can an online test confirm that my keyboard supports NKRO?

No. This test shows which simultaneous key presses reach your browser. It can report the highest number observed during your test, but it cannot certify your keyboard's hardware rollover capability or test combinations you did not press.