Keyboard test
The keyboard test lights up each key you press, so you can spot dead keys, double presses and the key repeat rate. No install needed.
While the test runs, keys no longer scroll the page. To stop it from the keyboard, press Esc twice quickly. If Esc does not work, click Stop test or switch tabs (Ctrl+Tab).
- Held now
- Tested
- Not tested yet
Runs in your browser. Test data stays on your device.
- Keys tested
- –
- Last key
- –
- Key repeat
- –
- Possible chatter
- –
Many keys at once
Hold several keys together to see how many your keyboard registers at the same time (rollover) and whether it drops some combinations (blocking) or reports keys you did not press (ghosting).
- Held now
- 0
- Most at once
- 0
Hold several keys at once. The verdict appears here.
- The Fn key and some key combinations never reach the browser.
- The result depends on the keyboard’s mode: some keyboards switch between 6-key and full rollover.
- The browser cannot tell a blocked key from one you did not press. If a key lights up on the map without a press, that is a phantom key, a sign of ghosting.
- The verdict counts regular keys. Shift, Ctrl, Alt and Win are reported separately, so they do not use up the 6 places.
How to use the keyboard test
- Click Start keyboard test.
- Press every key once. Each key lights up on the map while you hold it and stays marked as tested afterwards.
- Hold one key down for a second or two to measure key repeat, and hold several keys together to see which of them stay lit.
- In Chrome or Edge on a computer, click Full screen: also catch Win and Alt+Tab to test the Windows key, Alt+Tab and Escape as well. On a Mac the button reads Full screen: also catch the Command key. Press Esc once to test it; two quick presses stop the test and close full screen.
- Click Stop test, or press Esc twice within 0.6 seconds, when you have finished.
While the test runs, keys do not scroll the page or move focus, and browser-reserved shortcuts still work. Continue test picks up where you stopped, and Reset clears the results. A phone or tablet needs a physical keyboard connected by USB or Bluetooth, because on-screen keyboards send no usable key codes.
What the results mean
The map shows which keys reached the browser, and four cells describe how the keys behaved. The map follows the physical keys, so it works with any layout. Pressing the extra key beside the left Shift switches the map to the 105-key ISO board.
| Result | What it means | What to do |
|---|---|---|
| A key lights up while held, then stays marked Tested | The browser received the key’s signal. | Nothing to fix. |
| A key stays Not tested yet | No signal reached the browser. The cause can be a dead switch, a loose connection or a key the keyboard handles itself, such as Fn. | Press it firmly and hold it. Try another USB port or another keyboard. |
| Keys tested: Every key responded | Every key on the map, and every extra key you pressed, sent a signal. | Nothing to fix. |
| Possible chatter: None so far | No key went down again within 30 ms of being released. | Nothing to fix. Check again after some typing, because a worn switch bounces only now and then. |
| Possible chatter: Found, with key names | A key was pressed again less than 30 ms after its release. Nobody does that on purpose, so the switch bounced. | Cleaning around the key may help for a while. If it keeps happening, replace the switch, or on a mechanical keyboard raise the debounce time if its software has one. |
| Possible chatter: a dash and “Not measurable” | The browser rounds its clock to steps of more than 5 ms, which is too coarse to time a bounce. | Use Chrome or Edge, or turn off fingerprinting protection while you test. |
| Key repeat: a rate per second, with a delay in ms | A held key repeated that many times per second after that waiting time. | Nothing to fix. Change the rate and delay in your system’s keyboard settings. |
| Right Alt labeled AltGr, Left Ctrl stays dark | Windows sends a left Ctrl signal together with every AltGr press, and the test takes it back. | Nothing to fix. Press Left Ctrl on its own to test it. |
Last key shows the printed legend, the key’s name, then the character the browser reports, the physical code and the position: standard, left, right or numpad. Key repeat needs a held key. The rate appears from the second repeat, and the delay appears only when the test saw the key go down. Both come from the system’s keyboard settings, so a slow repeat is usually a setting and not a faulty keyboard.
Keyboard test not working?
The keyboard test needs no permission. Most problems come down to what the system does with a key before the browser sees it.
Nothing lights up when I press a key
Click inside the page once, because keys typed into the address bar or another window do not reach the test. Then check the cable, the Bluetooth connection and the batteries. On a phone or tablet the test asks for a physical keyboard, because on-screen keyboards send no usable key codes and the test ignores them.
One key never lights up
On many laptops the keyboard handles Fn itself, so the browser may see nothing, or only the key that Fn produces. For an ordinary key, cleaning under the keycap may help. Try another USB port or another keyboard to see whether the key itself is at fault. Check the area below the board too: media keys and F13 and above appear under Other keys once pressed, and they are not on the map before that.
The Windows key opens the Start menu, or Alt+Tab switches windows
Use full screen in Chrome or Edge on a computer. After you click the full-screen button, the Windows key, Alt+Tab, Escape and most browser shortcuts reach the test instead of the system, and shortcuts such as Ctrl+Alt+Del and Win+L always stay with Windows. Hold Esc or click Exit full screen to leave. Firefox and Safari cannot capture these keys, so they show a hint to open the test in Chrome or Edge. A phone or tablet with only a touchscreen shows neither the button nor the hint.
System keys could not be captured
This message appears in full screen when the browser refuses to hand the page the system keys. Every other key is still tested. Leave full screen with the button and try again.
A key types double letters, or chatter shows up
Dirt, a worn switch or a low debounce setting causes it. Blowing out dust from under the key may help for a while, so test again afterwards. If one key keeps appearing, replace its switch or test the keyboard on another computer. If letters double in documents but chatter stays at None, the second press may come later than 30 ms, so press that key many times and watch the count. If a key that doubled letters before now shows no chatter, the Windows accessibility option Filter Keys (Bounce Keys), when it is on, may be dropping quick repeated presses before the browser sees them. Turn it off while you test.
Chatter says “Not measurable”
Your browser hides precise timing, as Firefox does with resistFingerprinting and Tor Browser does. Open the test in Chrome or Edge, or turn that protection off while you test.
Right Alt does not light the left Ctrl
This is intended. Windows treats Right Alt as AltGr on layouts such as Polish (Programmers) and adds a left Ctrl signal to every AltGr press. The test discards a left Ctrl press that comes at most 5 ms before an AltGr press, so a broken left Ctrl cannot hide behind a working right Alt.
A key looks stuck as held
Another window took focus while you held the key, and its release never arrived. The test lets go of everything when the window loses focus, so press and release the key again. On a Mac, the system sends no key release for keys let go of while Command is held, so letting go of Command clears all held keys.
The test stopped by itself
Pressing Esc twice quickly stops it, and so does switching to another tab or leaving the page. Click Continue test to carry on with the same results.
Many keys at once: rollover and ghosting test
The Many keys at once panel under the results shows how many keys register together. Pick Games (W, A, S, D, Shift, Space), Ctrl + Shift + arrows, Six letters or Your own, and hold its keys together. A check mark means a key registered with the others; a cross in a dashed outline means it did not.
Held now counts the keys down at this moment, and Most at once keeps the highest count. The verdict counts regular keys only, because Shift, Ctrl, Alt and Win are reported separately. Six keys suggest USB 6-key mode (6KRO), seven to nine extended rollover, and ten or more full rollover (NKRO). Each figure is a minimum. If you hold every key of a combination and some never register, the panel names the missing keys and says the keyboard blocks that combination.
Fn and some combinations never reach the browser. Some keyboards switch between 6KRO and NKRO, and Bluetooth and BIOS-compatible USB modes often stop at six. A key that lights up on the map without a press is a phantom key, a sign of ghosting.
How we measure
The test listens to keydown and keyup events, identifies each key by its physical code, and takes times from the event timestamps. Possible chatter is a second press of a key less than 30 ms after its release, measured only when the browser clock ticks in steps of 5 ms or less. Key repeat is the rate between the first and last auto-repeat event of a held key, and its delay is the time from the press to the first repeat. A browser cannot see the switch itself, keys the system keeps for itself such as Ctrl+Alt+Del, or presses a keyboard filters out, so the figures describe only what reaches this page.
Frequently asked questions
How do I check that every key on my keyboard works?
Start the test and press each key once. The map has 104 keys, or 105 on an ISO board, and Keys tested reads “Every key responded” when all of them have sent a signal. A key that is still dark never reached the browser, and keys the map lacks, such as media keys, appear once you press them.
What should I do if my keyboard types the same letter twice?
Press the suspect key about 20 times and read Possible chatter, which names any key that went down again within 30 ms of its release. If a key shows Held now without you touching it, press and release it once first, because a key release lost after a focus change can leave it looking held. Try the keyboard on another computer to tell a worn switch from software.
What if the Esc key does not work and I cannot stop the test?
Click Stop test with the mouse or touchpad. In full screen there is no Stop button, so click Exit full screen first and then Stop test, or press Esc twice quickly if it works. If Esc stays dark on the map after you press it firmly, it sends no signal to the browser, so try another keyboard to confirm.
What is keyboard rollover (6KRO and NKRO)?
Rollover is how many keys a keyboard can report at the same time. A keyboard in USB 6-key mode (6KRO) reports up to six regular keys at once, plus Shift, Ctrl, Alt and Win (Command on a Mac). Full rollover (NKRO) reports every key you press together. Six keys are enough for typing and most games; NKRO helps with very fast typing (such as stenography), rhythm games and complex shortcuts.
What is keyboard ghosting?
Ghosting happens on keyboards whose keys share wires in a matrix. Press certain keys together and the keyboard may report a key nobody pressed (a phantom key) or drop one that was pressed (blocking). Laptops and budget keyboards are the usual cases; a keyboard with a diode under every key avoids it.
Is the keyboard test private?
Yes. Key presses are handled only in your browser, and keystrokes and results never leave your device. The test listens to the keyboard only while it runs.