SuperDevTools
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Keyboard test online

This tool tests physical keyboards. On a phone or tablet, plug in a USB keyboard or pair a Bluetooth one: the on-screen keyboard does not send the same information.

Click the keyboard picture or "Start test", then press every key.

  • pressed
  • tested
  • problem
  • not detectable

Last key

No key yet
Character (key)
–
Position (code)
–
Location (location)
–
Held together
0

Problems

Recent key log

Keys you press will appear here, newest at the top.

Physical position or typed character?

The keyboard picture tracks each key by its physical position, event.code, named after a US QWERTY keyboard: the A key on an AZERTY keyboard is therefore KeyQ. The character produced, event.key, depends on the layout set in your operating system. If the characters do not match the picture, change the layout above.

Keys a browser cannot always see
  • Fn: the keyboard handles it internally and sends nothing to the computer. Test it together with another key (Fn + F1, for example).
  • System key (the logo key on the bottom row): it is often detected, but the system may open its menu on release or keep shortcuts that use it for itself.
  • Print Screen: depending on the system, only the release arrives, or nothing at all. The tool counts the key as soon as it receives either one.
  • Browser and system shortcuts (close tab, new window, switch window, full screen, lock the session): they are handled before the page and cannot be blocked.
  • Media, brightness and volume keys: on some systems they act directly without telling the page.

Nothing is sent or saved: no keystroke is stored, and the log disappears when you close the page. Only your settings (layout, size, threshold) stay on this device.

What this keyboard test is for

This keyboard test draws a keyboard on screen and lights up each key while you hold it down. Once released, the key stays green, so you can see at a glance which keys work and which stay silent. It is a quick way to check a second-hand laptop before you buy it, to make sure a keyboard still works after cleaning or a spilled drink, or to find out why a letter sometimes appears twice when you type.

How to use the key tester

  1. Pick the "Layout" (QWERTY US is selected by default on this page, QWERTY UK is one click away) and the "Size": "Full size with numpad", "Tenkeyless (TKL)" or "Compact".
  2. Click "Start test" or the keyboard picture. While the test runs, Tab, Space, the arrows and F1 to F12 stay inside the test area.
  3. Press every key, one at a time. The counter shows, for example, "103 / 104 keys tested": one key left to try.
  4. To leave, click "Exit test" or hold Esc for one second. "Reset" clears everything so you can start again.

Reading the results

The "Recent key log" lists the last 15 presses with their hold time; a normal keystroke lasts roughly 60 to 150 ms.

The "Problems" panel flags a key held for more than 3 seconds (stuck, or held on purpose) and two presses of the same key less than 30 ms apart: a double press, often called key chatter, since nobody types that fast with one finger. The threshold goes from 5 to 250 ms. Auto-repeats, normal when you hold a key, are counted separately.

Physical position versus typed character

The physical position (event.code) is named after the key on a US QWERTY keyboard. The character produced (event.key) depends on the layout set in your operating system. On a UK keyboard, the key left of Enter sends Backslash as its code but types "#". The tool tracks keys by position, so if the picture does not match what you type, switch the layout.

Ghosting and N-key rollover

Past a certain number of keys held together, many keyboards drop presses or invent a phantom key: that is ghosting. N-key rollover is the number of keys read at once. Press several keys together and "Held together" shows, for example, "6 (max 6)". Try different groups, as the result changes from one area to another.

A key does not work: what to do

  • Unplug the keyboard or shut down the laptop, turn it upside down and tap it gently. Blow between the keys, and never push anything under a keycap.
  • Wireless keyboard: replace or recharge the batteries. Wired keyboard: try another USB port or another cable.
  • Connect the keyboard to another device. If the same key stays silent, the keyboard is at fault; if not, look at the computer.
  • If the keyboard is still under warranty, claim it rather than opening the keyboard yourself.

Keys a browser cannot see

Fn sends nothing to the computer, so it is hatched on the compact size and left out of the total. System and browser shortcuts (close tab, switch window) are handled before the page. The system key may open a menu, and Print Screen sometimes sends only its release; the tool still counts it.

Frequently asked questions

Does the test work on a phone?

The tool is meant for physical keyboards. On a tablet or phone, plug in a USB keyboard or pair a Bluetooth one: the on-screen keyboard does not send the same information.

Are my keystrokes recorded?

No. Nothing is sent or saved. Only your settings (layout, size, threshold) stay on your device.

Why does the counter not reach 104?

The total depends on the size and layout: 104 keys for a full US keyboard, 87 tenkeyless and 82 compact. A UK keyboard has one more key next to the left Shift, so 105, 88 and 83.

Is one double press a problem?

Once in a while, no. If the same key keeps showing up under "Problems", its switch is worn or dirty: clean it and run the test again.