This keyboard tester shows every key on a full size keyboard. Press a key and it lights yellow while it is held, then turns green once it is released. Keys you have not pressed stay dark, so after a run through the whole board the dead ones are easy to spot. It works with USB, wireless and Bluetooth keyboards on Windows, Mac, ChromeOS and Linux, and you can switch the picture to a laptop, Mac, tenkeyless or numpad layout with the buttons above it. There is nothing to download, so it works as a quick key tester on any computer with a browser.
How to test your keyboard
- Pick the layout that looks most like your keyboard. Mac visitors get the Mac layout automatically.
- Press every key once, row by row, at your normal typing speed. Include the modifier keys on both sides: Shift, Ctrl, Alt, the Windows or Command key.
- Look for keys that stayed dark. Press them again, firmly, in the middle of the keycap.
- Look for keys marked in orange with ×2. Those typed twice from one press.
- Hold several keys together, for example W, A, Shift and Space, and watch Keys held now. If one key does not light up while the others are held, your keyboard has a rollover limit on that combination.
- Press Copy results to save a summary you can paste into a support ticket or a warranty claim.
Some keys are taken by your system before the page sees them, such as the Windows key or Print Screen. In Chrome and Edge, Lock system keys puts the test in full screen and lets those keys through.
What the keyboard tester readouts mean
| Readout | What it tells you | Normal result |
|---|---|---|
| Keys tested | How many different keys have registered so far | Every key on your board, apart from Fn |
| Last key | The key name and the character it typed | The character printed on the key |
| Keys held now | How many keys the keyboard reports as down at this moment | Rises as you hold more keys |
| Press time | How long the last key was held, in milliseconds | 60 to 150 ms for a quick tap |
| Typed twice | Keys that sent a second press within 35 ms of letting go | 0 |
The key event log under the readouts lists each press and release with its exact code and timing. It is useful when a key types the wrong character, because you can see whether the keyboard sent the wrong key or your system turned the right key into the wrong letter.
A key does not light up
When a key stays dark no matter how you press it, the key press is not reaching the computer. Work through the causes from the most common:
- Dirt or a crumb under the keycap. On a mechanical keyboard, pull the cap off with a keycap puller and blow out the switch. On a laptop, tilt the machine and use short bursts of compressed air at an angle.
- A spill. Sticky or sugary drinks leave a film that stops the contacts closing. Unplug the keyboard and let it dry for at least 24 hours before testing again. Laptop keyboards that took a spill often need the keyboard replaced.
- A failed switch. If one key on a hot swap mechanical board fails, swap its switch with one from a key you rarely use. If the problem moves with the switch, replace the switch.
- Filter Keys on Windows. With Filter Keys turned on, quick taps are ignored. Open Settings, then Accessibility, then Keyboard, and turn Filter Keys off.
- A whole row or block is dead. Several neighbouring keys failing together points to the keyboard's internal circuit or a loose ribbon cable on a laptop, not to the switches.
If no key lights up at all, the computer is not getting anything from the keyboard. Follow the steps in our guide for when your keyboard not working, which covers cables, receivers, Bluetooth pairing and drivers.
A key types twice from one press
An orange key with ×2 sent two presses when you pressed it once. This is called key chatter. The metal contacts inside the switch bounce, and the keyboard reads the bounce as a second press. It shows up as double letters in your typing, such as "thhe" or "ballon".
- Blow out the switch with compressed air while pressing the key up and down 20 or 30 times.
- On a hot swap mechanical keyboard, replace the switch.
- Many gaming keyboards have a debounce setting in their software. Raising it a few milliseconds hides light chatter.
- If the keyboard is under warranty, chatter on a new keyboard is a fault worth claiming. Use Copy results as evidence.
A key stays lit or keeps repeating
A key that stays yellow after you let go is reported as still held down. A keycap rubbing against its neighbour or a bent stabilizer on Space, Enter or Shift can hold a key down. Press and release it a few times and check that it springs back fully. If the key stays lit with nothing touching it, the switch is shorted and needs replacing. On a laptop this often follows a spill.
Keys type the wrong character
If the Last key readout shows the right key name but the wrong character comes out in other apps, the keyboard is fine and the problem is the language or layout setting. Windows switches layouts with Windows key + Space or Alt + Shift, which is easy to press by accident. Remove layouts you do not use in Settings, then Time and language, then Language and region.
On laptops without a separate number pad, letters such as U, I, O, J, K and L can type numbers when Num Lock is on. Press Num Lock, or Fn with Num Lock, to turn it off. When this tester can read your layout, the letters on the picture follow it, so an AZERTY or QWERTZ keyboard shows its own letters.
Several keys at once do not all register
Hold W, A and Space together, then add Shift. If one of them refuses to light up, your keyboard has hit its rollover limit for that combination. Cheaper keyboards share wiring between keys, so certain combinations block each other. This is called ghosting. Gaming keyboards avoid it with what makers call anti ghosting or n key rollover. You can measure it properly with the n key rollover test, which shows exactly which combinations your keyboard blocks.
Keys a keyboard checker cannot read
| Key | Why it may not show | What to do |
|---|---|---|
| Fn | It never leaves the keyboard | Hold Fn and press a function key to test both |
| Windows key, Alt+Tab, Esc | The system takes them first | Use Lock system keys in Chrome or Edge |
| Print Screen | Windows only reports the release | It still counts, with no press time |
| Media and volume keys | Some keyboards handle them in their own software | They appear under Other keys when they arrive |
| Mac F1 to F12 | macOS uses them for brightness and volume | Hold fn, or change the setting in Keyboard settings |
Testing a laptop, Mac or wireless keyboard
Switch the picture to Laptop or Mac with the layout buttons, or open the dedicated laptop keyboard tester and keyboard test mac pages, which explain the keys those keyboards handle differently. For a wireless keyboard, test with fresh batteries and the receiver plugged into a port on the computer itself, since low batteries cause missed and repeated keys that look like hardware faults.
Gamers should also check timing. The keyboard latency test measures how long each key stays down and how evenly your presses arrive, and the spacebar counter shows how fast you can tap a single key. If your number keys are the problem, the numpad test shows the number pad on its own at a larger size. For a new mechanical board, the keyboard sound test listens through your mic and shows the loudest keys and any rattling stabilizer.
Keyboard tester questions
Is this keyboard tester safe to use?
Yes. The test reads key presses inside this browser tab and nothing else. What you type is not saved, logged to a server or sent anywhere, and closing the tab clears it.
Why does the Fn key not light up?
The Fn key is handled by the keyboard's own controller. It changes what the other keys send, but it never reaches the computer as a key press, so no keyboard checker can see it. Test it by holding Fn and pressing a key that has a second function, such as F1 to F12.
Why does pressing the Windows key open the Start menu?
Windows grabs that key before the browser sees it. In Chrome or Edge, press Lock system keys above the keyboard. The test goes full screen and the Windows key, Alt+Tab and Esc are passed to the page. Hold Esc to leave.
How do I test a keyboard for key chatter?
Tap each key once, at normal speed. If a single tap shows ×2 on the key and adds to the Typed twice count, the switch is bouncing. Repeat the key a few times. A key that does it more than once in ten taps needs cleaning or a new switch.
Can I test a keyboard on a phone or tablet?
Yes, if the keyboard is connected to the phone or tablet by USB or Bluetooth. The on-screen keyboard on a phone does not report which key position was pressed, so it cannot be tested here.
What is a good keyboard rollover result?
Most office keyboards register at least 3 keys at once in common combinations. Gaming keyboards usually register 6 or more, and many register every key. Hold the keys you use together in games, then read the Most at once value. For a full check, use the anti ghosting test.