Keyboard Double-Click Test
Check your keyboard for unwanted double key presses and switch chatter in seconds.
Click the box below to focus it, then press each key once with your normal rhythm. The tool times the gap between presses of the same key and flags any repeat too fast to be human as a likely double-press switch fault. Holding a key (auto-repeat) is ignored.
Ready to test
Press any key on the pad below. We measure the gap between presses of the same key and flag any repeat faster than 80 ms.
Press each key once with your normal rhythm. This tool measures the time between presses of the same key and flags any repeat that is faster than a human can press — the clearest sign of a failing key switch. Holding a key is ignored, so auto-repeat never triggers a false fault. Best used on a desktop with a physical keyboard.
Want to check every key for dead or stuck keys? Try the full Keyboard Tester.Keyboard Double-Click Test Guide
What is the Keyboard Double-Click Test?
The Keyboard Double-Click Test is a free online tool that detects when your keyboard registers a single physical key press as two presses. It records the exact time between consecutive presses of the same key and flags any repeat that arrives faster than a person could deliberately press it. That kind of unwanted repeat — known as chatter or a double-press fault — is one of the most common ways a keyboard fails, and this test makes it easy to confirm with precise key-press detection and a detailed event log.
How to Use the Test
- 1. Pick a fault sensitivity — 80 ms is the recommended default for most keyboards.
- 2. Click inside the test box so it captures your key presses.
- 3. Press the key you suspect once at a time, at a normal rhythm — do not hold it down.
- 4. Watch the live gap readout and the event log for any red “FAULT” entries.
- 5. Read the verdict and per-key results, then press Reset to start over.
How the Detection Works
Every time you press a key, the tool reads a high-resolution timestamp and subtracts the time of your previous press of that same key. A real, deliberate double tap is usually more than 100 milliseconds apart. A failing switch bounces electrically and fires the second press far faster — often in under 30 ms. Because no human finger can move that quickly, any same-key repeat below your chosen threshold is counted as a fault. Crucially, the operating system’s auto-repeat (from holding a key) is detected and ignored, so only genuine separate presses are ever timed.
Reading the Results
| Reading | What it means |
|---|---|
| OK | A normal press, well clear of the fault threshold. |
| FAULT | A repeat faster than your threshold — a likely switch fault. |
| Fastest Gap | The shortest interval seen — the lower it is, the more suspect the switch. |
| Per-key verdict | Each key you press is marked OK or FAULTY independently. |
What Causes Keyboard Chatter?
The culprit is the switch beneath each key. Over millions of presses its springy metal contact weakens and starts to bounce, so a single press makes and breaks contact several times in a few milliseconds. Dust, humidity, spilled liquids, and oxidation speed this up. The result is doubled letters when you type, repeated inputs in games, and characters appearing when you only pressed a key once. The fault almost always gets worse over time, so it is worth confirming early.
When to Run This Test
- • When letters sometimes appear twice even though you pressed a key once.
- • When a key occasionally repeats its input in games or while typing.
- • Before buying a used keyboard, or after receiving a new one.
- • When a warranty claim needs evidence of a key fault.
- • After cleaning or replacing a switch, to confirm the fix worked.
Frequently Asked Questions
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