Keyboard Ghosting & NKRO Test
Ghosting is when your keyboard misses a key because you're already holding several others, for example pressing W, A, Shift and Space at the same time. Keyboards with N-key rollover (NKRO) register every key, no matter how many you hold.
Press several keys at once and this test shows which ones registered, how many your keyboard can handle together, and whether any combinations get blocked.
Keyboard Ghosting & NKRO Tester
Test simultaneous key presses on a virtual keyboard to detect ghosting and measure rollover limits.
How to use it
- Click inside the test area so the page can read your keyboard.
- Hold down as many keys as you can at once. The on-screen keyboard lights up each one that registers.
- Try the combinations you use in games, such as W + A + Shift + Space.
- Read the maximum number of keys registered together.
What your results mean
What your result means:
Keys registered together Means
2â3 Basic office keyboard; ghosting likely in games
- Common USB limit (6-key rollover); fine for most games
All keys pressed N-key rollover; no ghosting
Combinations worth testing
Game type Try
Shooters W + A + Shift + Space + R
MOBAs and strategy Q + W + E + R + Ctrl
Two players on one keyboard W A S D and the arrow keys at the same time
Some keyboards only use NKRO in a gaming mode or over USB rather than Bluetooth. Check the manual if your result is lower than advertised.
Why keyboards ghost
Most cheaper keyboards wire their keys in a grid to save cost. When you press certain combinations, the keyboard can't tell which keys are really down, so it blocks some of them. That blocked key is the ghost.
Gaming keyboards wire each key so it can be read on its own, which is what N-key rollover means. That's why the same combination can fail on one keyboard and work perfectly on another.
Rollover explained
Rollover is the number of keys a keyboard can register at the same time. A keyboard with 6-key rollover can register six keys together, plus modifier keys like Shift and Ctrl. N-key rollover means every key can be registered at once.
Most games only need a handful of keys at once, so even basic keyboards are fine for many players. Problems usually appear with particular combinations, like moving diagonally while sprinting and jumping.
Rollover type Keys at once Typical keyboards
2-key rollover Two, with ghosting beyond Older or very basic keyboards
6-key rollover Six plus modifiers Many office and gaming keyboards
N-key rollover Every key Most gaming keyboards
Ghosting versus blocking
Strictly, ghosting means the keyboard reports a key you didn't press, while blocking (or jamming) means it ignores a key you did press. Most modern keyboards block rather than ghost, but people often call both ghosting.
This test shows both. If a key you pressed doesn't light up, it's being blocked. If a key you didn't press lights up, that's true ghosting.
Testing gaming combinations
Press the combinations you use in your games. A common one is W and D to move diagonally, with Shift to sprint and Space to jump. Add a key for a weapon or an action, and check every key lights up.
If a combination fails, try changing which keys you use for that action in the game. Moving one action to a different key often avoids the blocked combination.
USB and N-key rollover
Some keyboards only offer full N-key rollover in a particular mode, because older computers and BIOS screens expect a simpler 6-key mode. Check your keyboard's software or manual for an NKRO setting.
If your keyboard has both a USB and a wireless mode, rollover can differ between them. Test both.
Laptop keyboards
Laptop keyboards are often built more cheaply than gaming keyboards and may block some combinations. If you play on a laptop, test your usual combinations here.
If they fail, an external gaming keyboard is the simplest fix.
Wireless keyboards
Some wireless keyboards have lower rollover than wired ones, especially over Bluetooth. Gaming wireless keyboards using their own receiver usually match wired performance.
If combinations work wired but not wirelessly, the wireless connection is the limit.
Checking for stuck or chattering keys
Use the test to check single keys too. A key that stays lit after you release it is sticking. A key that flickers or appears twice from one press is chattering, a common fault on worn mechanical switches.
Cleaning under the key cap can fix sticking. Chattering usually needs the switch cleaning or replacing.
Keyboards and anti-cheat
Some keyboards include features like rapid trigger, adjustable actuation and Snap Tap-style direction handling. A few games and tournaments restrict certain features. If you play competitively, check the rules before using them.
This test shows key presses as the keyboard reports them, so it can help you check how these features behave.
Choosing a keyboard for gaming
For gaming, look for N-key rollover, a comfortable layout and switches you enjoy. Mechanical and magnetic switches both work well. Magnetic switches often let you adjust how far a key must travel to register.
Rollover is usually listed in the product description. If it isn't, it may be limited.
What to do if your keyboard fails
If a combination you need fails, first try remapping in the game. If that doesn't work, check for an NKRO mode. If none helps, consider a gaming keyboard with N-key rollover.
Test any new keyboard here when it arrives, while you can still return it.
How to use the test
Press and hold several keys at once and watch which ones light up. Add keys one at a time until one fails to light. That shows your keyboard's limit for that combination.
Try different combinations. Some keyboards handle certain groups of keys better than others because of how they're wired.
Common problem combinations
Combinations near the WASD keys often cause problems on cheaper keyboards because those keys are close together in the wiring. Test W, A, S, D with Shift, Ctrl and Space, as well as nearby number keys.
Keyboards for music and typing
Rollover matters for musicians using keyboards as MIDI controllers and fast typists too. If letters disappear while typing quickly, rollover may be the cause.
Magnetic and optical switches
Magnetic and optical keyboards sense key presses without traditional contacts. They usually support full rollover and can offer adjustable actuation, which changes how far you must press a key.
Testing a new keyboard
When a new keyboard arrives, test the combinations you use most, as well as every key on its own. Check for stuck, chattering or missing keys, and confirm the rollover matches what was advertised.
If you find a problem, you can still return the keyboard within the shop's returns period.
Gaming keyboards with 6-key rollover
Some gaming keyboards use 6-key rollover by default and need N-key rollover turning on. Check the keyboard's software or manual. A key combination may be needed to switch modes.
Remapping keys to avoid problems
If your keyboard blocks a combination you need, remapping can help. Move an action to a key that doesn't conflict. Most games let you change key bindings in their settings.
Use the test to find a combination that works before changing your game settings.
Membrane keyboards
Membrane keyboards use a rubber layer under the keys and are common on cheaper keyboards. Many have limited rollover. If you're gaming on a membrane keyboard and notice missed keys, a mechanical or magnetic keyboard with full rollover can help.
Ghosting on laptops used for gaming
Gaming laptops often advertise anti-ghosting on certain keys, usually around WASD, rather than full rollover across the whole keyboard. That's fine for many games, but combinations involving other keys may still fail. Test the keys you actually use, especially if you play games with many bindings, like strategy games or MMOs.
Common problems
Make sure the test area is selected, then try again. If the same combination fails every time, that's ghosting.
Some special keys aren't passed to the browser. That's normal.
Frequently asked questions
What is NKRO?
N-key rollover: the keyboard registers every key pressed at the same time.
Do I need NKRO for gaming?
6-key rollover covers most games. NKRO helps in fast games and when two people share a keyboard.
Is 6-key rollover enough?
For most games, yes. Some combinations may need more.
What does NKRO mean?
N-key rollover: every key can be registered at once.
Why does a key light up that I didn't press?
That's true ghosting, usually on cheaper keyboards.
Does this test work on Mac?
Yes. It runs in any modern browser.
Can software fix ghosting?
No. It's a hardware limit, but remapping keys can avoid it.
Can I fix ghosting with drivers?
No. Rollover is a hardware limit.
Does anti-ghosting mean N-key rollover?
Not always. Anti-ghosting may only cover some keys.
Do wireless keyboards ghost more?
Some do over Bluetooth. Gaming wireless keyboards usually don't.
Why do some key combinations work and others don't?
It depends on how the keys are wired inside the keyboard.
Can a USB hub cause missed keys?
Rarely. Plug the keyboard directly into the computer to rule it out.