# Keyboard Ghosting Test

> Free keyboard ghosting test: check n-key rollover (NKRO), find blocked keys, test combos like W + A + Shift + Space, and detect key chatter on a live on-screen keyboard. No download.

Check how many keys your keyboard can register at the same time and whether it drops keys in gaming combos. Hold several keys at once and a full on-screen keyboard lights up every key it receives. The test records your maximum rollover and ticks off combos for FPS, MOBA, rhythm, typing and arrow-key games. It also flags key chatter (one press registering twice) and logs every press with its hold time. If a key never lights up while others are held, your keyboard is blocking it.

- **Live tool:** https://www.toolnova.org/diagnostics-tools/keyboard-ghosting-test
- **Category:** Speed Test & Diagnostics (https://www.toolnova.org/diagnostics-tools)
- **Price:** Free
- **Requirements:** Runs in a modern web browser · No signup · No install

## What this tool does

- Live on-screen keyboard (full, TKL or 60% layout) that lights up held keys and marks every key you've tested.
- Maximum rollover counter with a 2KRO, 6KRO or NKRO-class verdict and the exact key set that achieved it.
- Combo checklists for FPS, MOBA, rhythm, typing and arrow-key games that pass when every key registers at once.
- Key chatter detection: flags a key that fires again within 30 ms of release.
- Event log with press and release, keys held and hold time in milliseconds.
- Keys-tested coverage counter for checking every key on a new keyboard.
- Identifies keys by physical position, so it works with any language layout; blocks page scrolling while you test.

## How to use Keyboard Ghosting Test

1. **Click the page** — The page needs focus to read your keyboard.
2. **Hold keys together** — Press and hold as many keys as you can. The counter and on-screen keyboard show how many the keyboard reports at once.
3. **Try each combo** — Pick FPS, MOBA, Rhythm, Typing or Arrows and hold every key in a combo card at the same time. It turns green when all of them register.
4. **Check for chatter** — Press suspect keys slowly, one at a time. Red keys and red log lines mean a key fired twice.

## Common use cases

- Checking a gaming keyboard really supports NKRO
- Finding why a key stops working while running and jumping in a game
- Diagnosing a key that types double letters (chatter)
- Testing every key on a new or used keyboard
- Comparing keyboards before returning one
- Testing a laptop keyboard for rollover limits

## About

### What is keyboard ghosting?

Keyboards wire their keys in a grid of rows and columns. When three keys that share rows and columns are held, a cheap keyboard cannot tell which keys are really down, so it either reports a key that was not pressed (a ghost key) or, more often on modern boards, blocks the extra key entirely. Rollover is the number of keys a keyboard can report correctly at once. Gaming keyboards add diodes or use different scanning so every key is read independently, which is called n-key rollover or NKRO.

| Rollover | Typical keyboards | Gaming impact |
| --- | --- | --- |
| 2KRO | Basic membrane and older office boards | Drops keys in movement + jump combos |
| 6KRO | Many USB keyboards in boot mode | Fine for most games |
| NKRO | Mechanical and gaming keyboards | Every key registers |

### Ghosting, blocking and chatter compared

Three different faults can make a keyboard feel unreliable. Blocking (often loosely called ghosting) is a key that doesn't register while others are held. True ghosting is a key that appears without being pressed. Chatter is a single press registering twice, usually because a mechanical switch is worn, dirty or bouncing. This test shows all three: blocked keys never light up, ghost keys appear in the held list, and chatter shows as red keys and log lines.

| Problem | What you notice | Fix |
| --- | --- | --- |
| Blocking | A key stops working in combos | NKRO keyboard or different keys |
| Ghosting | A key you didn't press appears | Keyboard with anti-ghosting |
| Chatter | Double letters from one press | Clean or replace the switch |

### Why a combo might fail even on a good keyboard

Some combinations are intercepted before the browser sees them: Windows and macOS shortcuts with Ctrl, Alt or the Windows key, laptop Fn layers, and gaming software macros. A few keyboards run 6KRO over USB by default and need a switch or key combination to enable NKRO. Bluetooth keyboards, USB hubs and KVM switches are often limited too. If a combo fails, try the right-hand modifiers or another USB port, and check the keyboard's manual.

See also: [Keyboard Test (every key)](https://www.toolnova.org/diagnostics-tools/keyboard-test), [Spacebar Counter](https://www.toolnova.org/diagnostics-tools/spacebar-counter), [Typing Speed Test](https://www.toolnova.org/diagnostics-tools/typing-test), [Double Click Test](https://www.toolnova.org/diagnostics-tools/double-click-test)

## FAQ

### How do I test keyboard ghosting?

Click the page, then press and hold several keys together. Watch the on-screen keyboard and the combo checklist. If a key never lights up while specific other keys are held, the keyboard is blocking it.

### What is NKRO?

N-key rollover means every key is read independently, so any number of keys held at once are all registered. Most mechanical gaming keyboards support it.

### Is 6-key rollover enough for gaming?

For almost every game, yes. Six keys plus modifiers covers movement, sprint, jump and an ability at once. Rhythm games and some fighting games can use more.

### How do I test for key chatter?

Press the suspect key slowly, one press at a time. If the event log shows a second press within a few milliseconds of release, or the key turns red, the switch is chattering.

### Why does my laptop fail the combos?

Many laptop keyboards have limited rollover to keep costs and wiring simple, and Fn layers can block keys. An external keyboard is usually the fix.

### Can the test detect ghost keys?

It shows every key the browser receives. If a key you are not pressing appears, that is a ghost key. Modern keyboards usually block extra keys instead of ghosting them.

### Does it work with non-English keyboard layouts?

Yes. Keys are identified by their physical position, so AZERTY, QWERTZ and other layouts work. The on-screen keyboard shows US labels.

---

ToolNova — free, privacy-first browser tools. Most tools process data locally on your device. See https://www.toolnova.org/llms.txt for the full directory.