Keyboard Double Typing Test
To find a key that types twice, press each suspect key slowly, about once a second, twenty times. If the test shows two presses of the same key closer together than the limit, shown in red, the key is bouncing. Holding a key down does not count: the automatic repeat of your system is ignored.
Double typing test
You need a physical keyboard for this test. On a phone or tablet, connect a keyboard by Bluetooth or USB first. The on-screen keyboard of a phone does not report which physical key you pressed.
Click here first, so the page receives your key presses.
The page lost focus, perhaps because of Alt+Tab, the Windows key or a shortcut. Click anywhere on the page and continue.
- Held now
- Worked
- Suspected double press
- Held 2 s or longer
- Not pressed yet
- Usually invisible to browsers
Gaps between presses of the same key (red = suspected double)
Keys with suspected doubles
Last keys
Keys that are not on this picture
How it works
Press keys on your keyboard. Each key lights up on the picture while you hold it and stays teal once it has worked. The page reads the key events your browser already gives every web page and never sends them anywhere.
This test needs JavaScript. The explanations below work without it.
How to do it
- Click once on the page.
- Press a suspect key slowly, about once a second, twenty times.
- Look for red gaps in the list and red keys on the keyboard.
- Repeat for other keys, and adjust the limit if needed.
How the test decides
For every key the test records the time of each new press. If a key is pressed again sooner than the limit after its previous press, the second press is marked as a suspected double. Events your system sends while you hold a key down are marked as repeats by the browser and are left out.
Start with the default of 60 ms. A bouncing switch usually produces gaps much shorter than any deliberate double tap. If you tap fast on purpose and get flagged, lower the limit. If a key types double in your documents but is never flagged, raise it.
Not the keyboard?
If no doubles show up here but you still get double letters, check the repeat delay in your system settings, Filter Keys or Bounce Keys on Windows, and the text app itself. The fix guide covers each step.
Frequently asked questions
Why does my keyboard type double letters?
Usually a worn or dirty switch bounces and sends two presses for one. A very short repeat delay in your system settings can also make a slightly long press repeat. This test separates the two: real repeats are ignored and only extra presses are flagged.
What limit should I use?
Start with 60 ms. Bouncing switches usually give gaps far shorter than a deliberate double tap. Lower it if your intentional fast taps are flagged, and raise it toward 150 ms if a key doubles in normal typing but is not flagged.
Does holding a key count as a double?
No. When you hold a key, the system sends repeat events, and the browser marks them as repeats. The test ignores them, so only new presses are compared.
Last updated: November 2, 2026