Press every key to check it works: each one lights up on a full-size, TKL, 75% or 60% keyboard, with rollover, repeat rate and stuck key checks.
Runs in your browser. Your keystrokes are not saved or sent anywhere.
- Press any key on your keyboard
- Watch it light up on screen
- Spot keys that do not register
This test needs a physical keyboard. On a phone or tablet, connect a USB or Bluetooth keyboard, then press any key. The on-screen keyboard can’t be tested here.
Press any key to start. Keys light up while held and stay green once tested.
Last key
key- -
code- -
keyCode- -
- Location
- -
- Event
- -
- Held for
- -
- Shift
- Ctrl
- Alt
- Win
- Caps Lock
- Num Lock
Rollover and ghosting
0 held now 0 most at once
Hold several keys at the same time. The count shows how many your keyboard reports at once.
What are rollover and ghosting?
Key rollover is how many keys a keyboard can report at the same time. N-key rollover (NKRO) means every key can be held at once. Keyboards in basic USB mode report at most 6 keys plus the modifiers (6KRO).
Ghosting is when a key you did not press lights up while you hold a few others. Many keyboards block the extra key instead, so a key you are pressing stays dark. Try the keys you use together, such as W, A, S, D with Shift and Space. Stuck key warnings wait while you hold three or more keys.
Key repeat
- delay - per second
Hold any letter key for two seconds to measure how long your computer waits before repeating it, and how fast it repeats.
Keys not tested yet 0
Other keys detected
These keys work but are not on the layout shown.
Event log 0
| Time | Event | key | code | keyCode | Location | Modifiers |
|---|---|---|---|---|---|---|
| Key presses and releases appear here, newest first. | ||||||
Keys that may not light up
- Fn (Globe on a Mac) is handled by the keyboard or the operating system, so no website can see it. Fn combinations show up as the key they produce.
- Media, brightness and volume keys are usually handled by your operating system and may not reach the browser.
- On a Mac, the top row controls brightness and volume by default. Hold fn (or Globe) to test F1 to F12.
- Print Screen on Windows only reports its release, which still counts here.
- On most 60% keyboards, the key left of 1 is Esc. The backtick it types with Fn shows under Other keys detected.
- Safari on a Mac can swap the key left of 1 and the key next to left Shift on ISO keyboards, so pressing one lights up the other. Both still count.
- System shortcuts such as Ctrl+Alt+Delete, Alt+Tab and the Windows key combinations are taken by the operating system, and browsers keep Ctrl+W, Ctrl+T and Ctrl+N for themselves. The tester never blocks them.
- To leave the test area with the keyboard, press Esc and then Tab.
How it works
- Press any key on your keyboard
- Watch it light up on screen
- Spot keys that do not register
What the keyboard tester does
A keyboard tester, or key tester, shows whether each key on your keyboard reaches your computer. Press a key and it lights up while held, then stays green, so you can check every key, find dead, stuck or double-typing keys, and see how many keys register at once. It covers full-size, TKL, 75% and 60% keyboards, ANSI or ISO, with Windows or Mac keys.
- Works with: USB, Bluetooth and laptop keyboards on Windows, macOS, Linux and ChromeOS, in current desktop browsers.
- Shows:
key,code,keyCode, left or right side, modifiers, hold time, keys held at once, and repeat delay and rate. - Limits: keys handled inside the keyboard or by the operating system, such as Fn, can’t be seen by any website.
- Privacy: keystrokes stay in this browser tab, and the log is only copied or downloaded when you ask.
How to use the keyboard tester, step by step
- Choose your keyboard’s size, ANSI or ISO, and Windows or Mac keys. On a Mac, Mac keys are picked for you.
- Click the keyboard picture, or start typing while it is on screen.
- Press every key once. Keys turn dark while held and green once they work. Keys not tested yet lists the rest.
- If a key stays grey, its signal is not arriving. Press it firmly a few times, then clean under it or check the connection.
- Hold several keys together to test rollover, or one key for two seconds to measure repeat.
- Copy the results, or download the log as CSV for a repair shop or support team.
Keyboard tester for ghosting and n-key rollover
Key rollover is how many keys a keyboard can report at the same time. N-key rollover (NKRO) means every key is detected, however many are held. Keyboards that use the basic USB boot protocol are limited to 6 keys plus the 8 modifier keys, known as 6-key rollover (6KRO).
Ghosting happens on keyboards wired as a grid: pressing three keys in a certain pattern can make a fourth, unpressed key register. Many keyboards prevent this by ignoring the third key, which is called blocking or jamming. To test, hold the keys you use together, such as W, A, S and D with Shift and Space.
| What you see | What it means |
|---|---|
| The count keeps rising as you add keys | Likely n-key rollover (NKRO) |
| The count stops at 6 letters, but Shift and Ctrl still add | 6-key rollover, the USB boot protocol limit |
| A key you are holding stays dark | Blocking: the keyboard dropped it in this combination |
| A key you did not press lights up | Ghosting: a phantom press caused by the wiring |
Keys a keyboard test can’t see
A page only receives the key events that the keyboard and operating system pass on. Each event carries a code that names the physical key position whatever the layout, as the MDN reference for KeyboardEvent.code explains. Keys that send no event can look broken when they work fine.
| Key | Why it may not light up | What to do |
|---|---|---|
| Fn or Globe | Handled by the keyboard or the operating system, so no event reaches the browser | Hold it with another key: the combined key shows up |
| F1 to F12 on a Mac | By default they control brightness, volume and other features | Hold fn while pressing them |
| Print Screen on Windows | Windows reports only its release, not the press | Nothing: the release counts as tested |
| Media and volume keys | Often handled by the operating system | If they arrive, they are listed under Other keys |
| Ctrl+Alt+Delete, Alt+Tab, Windows key shortcuts | The operating system takes them first | Test each key on its own |
| Ctrl+W, Ctrl+T, Ctrl+N | Chrome keeps these shortcuts for itself | Test Ctrl and the letter separately |
Two quirks are handled: the fake Left Ctrl press Windows sends with AltGr is ignored, and keys pressed with Command held on a Mac, which never report their release, are released with Command.
Keyboard tester for laptops and Macs
For a MacBook or the compact Magic Keyboard, choose 75% / laptop with Mac keys. This view shows fn, control, option and command, with half-height up and down arrows. Full size with Mac keys adds F13 to F19 for extended keyboards. Windows laptops vary, so pick 75% / laptop or TKL, whichever looks closer. Missing keys simply stay grey.
Not sure whether your keyboard is ANSI or ISO? Look at the Enter and left Shift keys.
| Layout | Full-size keys | Enter key | Left Shift |
|---|---|---|---|
| ANSI (common in the US) | 104 | Wide, one row tall | Long |
| ISO (common in Europe) | 105 | Tall, L-shaped | Short, with an extra key beside it |
TKL keyboards drop the number pad: 87 keys on ANSI, 88 on ISO. Press the extra ISO key while ANSI is selected and the tester switches to ISO.
Why a key types twice or keeps repeating
Key chatter, which this keyboard tester catches, is when one press registers more than once, which shows up as double letters. Common causes are dust in the switch, worn contacts and the keyboard’s debounce settings. The tester puts an orange dot on a key when a second press arrives less than 30 ms after its release, and warns when a key is held for 4 seconds with no release, a sign of a stuck key.
Hold a letter for two seconds and the tester measures the pause before it repeats and the repeat rate. Windows allows a repeat delay of about 250 ms to 1 second and a rate of about 2.5 to 30 repeats per second. On a Mac, change them in System Settings, Keyboard, under Key repeat rate and Delay until repeat.
Frequently asked questions
Is this keyboard tester safe? Does it record what I type?
Yes. Your keystrokes are not saved or sent anywhere: the event log lives in this browser tab and disappears when you leave. The page counts anonymous events such as a test starting, never which keys you press.
How do I test my keyboard keys online?
Pick your keyboard’s size and layout above, then press every key in the keyboard tester. Each key that works turns green, and the counter shows how many are left.
Why does a key not light up when I press it?
In the keyboard tester, either the key is not sending a signal, or browsers can’t see it, as with Fn. If it also fails in other apps, clean under the keycap, reconnect the keyboard or try another USB port.
What is keyboard ghosting?
Ghosting is when a keyboard registers a key you did not press while you hold several others. Many keyboards block the extra key instead, so a key you are pressing may stay dark.
What is n-key rollover?
N-key rollover (NKRO) means a keyboard can report every key held at the same time. Hold seven or more letters together: if all of them light up, your keyboard goes beyond 6-key rollover.
Can I test a MacBook keyboard?
Yes. The keyboard tester has a MacBook layout: choose 75% / laptop with Mac keys. Hold fn to test F1 to F12, as they control brightness and volume by default.
Does the keyboard tester work on a phone or tablet?
Only with a physical keyboard. Connect a USB or Bluetooth keyboard, then press any key. On-screen keyboards can’t be tested here.
More free tools
Device testsMouse TestCheck every mouse button, the scroll wheel and the polling rate, and catch unintended double clicks from a worn switch, right in your browser.
Device testsDead Pixel TestCheck any screen for dead, stuck and hot pixels with full-screen colours, test backlight bleed, banding and sharpness, and try the stuck pixel fixer.
Device testsMic TestCheck your microphone in seconds: live level, background noise and instant playback.
Built and maintained by the GradientCo team. Last updated 7 October 2026. Found a problem? Tell us.