A key that skips, repeats, or does nothing can come from the app, the keyboard layout, the connection, or the keyboard itself. Start with a clean key-by-key test, then use your device tools to pin down whether the problem is software or hardware.
Here are the fastest checks first, followed by deeper Windows, Mac, Chromebook, Linux, and manufacturer diagnostics.
1. Test Every Key Online First
Use a browser keyboard checker when you want the quickest answer without installing anything.
- 1.Open KeyboardChecker.com in a desktop browser.
- 2.Click anywhere on the page so it can receive your key presses.
- 3.Press each physical key on your keyboard.
- 4.Watch for working keys to turn green.
- 5.Use the page's special-key and numpad controls when testing those areas.
- 6.Press several keys together to check basic ghosting behavior.
KeyboardChecker works in current desktop browsers on Windows, macOS, ChromeOS, and Linux. Browser and operating-system shortcuts can intercept some keys before the page receives them. KeyboardChecker also cannot distinguish left and right Shift, Control, Alt, and Command or Windows keys, and grey keys cannot be tested.
For a second pass, open OnlineMicTest Keyboard Test, then press each key and confirm it lights up on the virtual keyboard. Its on-screen layout resembles a general English or American keyboard and is not an exact match, so keys may sit in different spots than on your physical keyboard. When your layout or language does not match, use the OS input-source or Keyboard Viewer steps below to check character mapping.
2. Confirm It Outside the Problem App
If one app is acting strange, test the same keys in a plain text field.
On Windows: Open Notepad, then type the problem letters, numbers, punctuation, Backspace, Enter, and Space.
On Mac: Open TextEdit, type the same keys, then compare the result with the app where the problem started.
Dell recommends testing in another application such as Notepad when the issue happens only in one program. This check is good for normal typing keys. Use a keyboard checker or system diagnostic for function keys, modifier keys, rollover, and media keys.
3. Check Lock Keys and Layout Settings
- Press Num Lock, then test the keypad numbers in a text field.
- Press Caps Lock, confirm the indicator or state changes, then type a few letters.
- On Mac, press and hold Caps Lock until the indicator light comes on.
- On a Mac with Media Eject, press and hold Media Eject until the eject icon appears.
If keys type the wrong symbols, check the selected layout. On Mac, open Apple menu > System Settings > Keyboard > Text Input > Edit, select an input source in the sidebar, then press Option, Shift, or both together to see how the layout changes.
4. Use Built In Keyboard Tools on Your Device
On Windows 11: Select Start > Settings > Accessibility > Keyboard, then turn on On-Screen Keyboard. You can also press Windows logo key + Ctrl + O. To test numpad behavior, open Options and turn on Turn on numeric keypad.
On Windows 10: Select Start > Settings > Ease of Access > Keyboard > Use the On-Screen Keyboard.
On Mac: Click the Input menu in the menu bar, then choose Show Keyboard Viewer. If the Input menu is missing, open Apple menu > System Settings > Keyboard > Text Input > Edit, then turn on Show Input menu in menu bar. Press physical keys and compare the viewer or typed input. Use Option and Shift to see alternate characters.
On Chromebook: Open Settings, search for diagnostics, then select Diagnostics > Input > The internal keyboard. Select Test and follow the prompts. Diagnostics is available on ChromeOS version 90 and later. You can also open Settings > About ChromeOS > Diagnostics. Stay in the same window during the test because keys are not tested while another window is active.
5. Fix Connection and Response Problems
External keyboards need a quick physical check before driver work.
- 1.For a USB keyboard, unplug the cable, wait briefly, then plug it back in.
- 2.Try a different USB port.
- 3.Bypass the USB hub.
- 4.Inspect the cable for damage.
- 5.For a wireless keyboard, check the batteries or charge.
- 6.Make sure the keyboard power switch is on.
- 7.Reseat the USB receiver or reconnect Bluetooth.
- 8.Test the keys again in a text field or keyboard checker.
On Mac, make sure a Bluetooth keyboard is on and charged, disconnect and reconnect Bluetooth, reconnect wired keyboards, try a different port or a different Mac, or connect a different keyboard to this Mac.
Mac accessibility settings can also change key response. Open Apple menu > System Settings > Accessibility > Keyboard and turn Slow Keys off. Then open Apple menu > System Settings > Accessibility > Pointer Control and turn Mouse Keys off. You can also press Option + Command + F5 and deselect Mouse Keys.
6. Try Another Computer or Repair Windows Drivers
Connect the keyboard to another PC and test the same keys. Microsoft says that when the device does not work on the other PC, it may need replacement. Make sure the required drivers are installed on the test PC.
If the keyboard works on another PC but fails on your Windows computer, reinstall the device driver. Right-click Start, select Device Manager, expand Keyboards or the relevant device category, right-click the keyboard, choose Uninstall device, select Uninstall, then restart from Start > Power > Restart.
After a recent update, use rollback when Windows offers it. In Device Manager, open the device, select Properties, open the Driver tab, select Roll Back Driver, choose a reason, select Yes, and restart when prompted. Rollback requires administrator permissions and appears only when a previous driver is available.
Skip old Windows Keyboard troubleshooter instructions for current Windows 11. Microsoft lists the legacy inbox Keyboard troubleshooter among the troubleshooters being removed, with MSDT platform removal scheduled for 2025.
7. Run Dell HP or Lenovo Diagnostics
On Dell: Open Start > All apps > SupportAssist > Troubleshooting, expand I want to troubleshoot my PC, choose I want to check a specific piece of hardware > Other Devices > Keyboard, then follow the prompts and choose Pass or Fail. Dell also offers online keyboard diagnostics through Dell Support with SupportAssist, plus pre-boot diagnostics from the F12 One Time Boot Menu.
On HP: Open HP PC Hardware Diagnostics, choose Component Tests > Input Devices > Keyboard Test, click Run once, and follow the instructions. HP's test ends when the tasks are completed or after 3 minutes. HP's hardware-failure keyboard test does not currently support Bluetooth devices.
On Lenovo: Open the current Lenovo Diagnostic Solutions download page, choose the diagnostics package for Windows, Linux, UEFI, or ChromeOS, then run the relevant hardware or input diagnostics for your model.
Run interactive diagnostics on the keyboard with the issue. Use pre-boot diagnostics when you need to test below the operating system.
8. Test Rollover and Linux Input Events
For gaming keyboards and shortcut-heavy workflows, test multiple keys at the same time. Open KeyboardTester.io Key Rollover Test, press several keys together, and confirm every key registers on screen. Browser and operating-system shortcuts can still intercept some combinations.
On Ubuntu with GNOME, open Activities, start typing Accessibility, click Accessibility, select Typing, then switch Screen Keyboard on. Use it to compare text entry from the on-screen keyboard against the physical keyboard.
Advanced Linux users can open Terminal and run sudo libinput debug-events, press the keyboard keys, and watch for key events. Use Ctrl + C to stop. For device discovery, run libinput list-devices or libinput list-kernel-devices first. In Linux input events, value 1 means key press, value 0 means release, and value 2 can mean repeat.
Frequently Asked Questions
What is the fastest way to check if keyboard keys work?
Open KeyboardChecker.com in a desktop browser, click the page, then press each key. Working keys turn green on the virtual keyboard.
Why does an online keyboard tester miss some keys?
Browser or operating-system shortcuts can intercept keys before the page receives them. KeyboardChecker also cannot distinguish left and right Shift, Control, Alt, and Command or Windows keys.
How do I know if a keyboard problem is only in one app?
Type the same keys in Notepad on Windows or TextEdit on macOS. If they work there but fail in one app, the problem is limited to that app.
How do I test a Chromebook keyboard?
Open Settings, search for diagnostics, then go to Diagnostics > Input > The internal keyboard. Select Test and stay in the same window while the test runs.
When should I replace a keyboard?
Connect it to another PC and test the same keys. Microsoft says that when the device does not work on the other PC, it may need replacement.
