How to test your keyboard
- Click once on this page so it has focus.
- Press every key one by one. Each key that works turns green.
- Hold several keys at the same time to see how many your keyboard can register together.
- If a key never turns green, press it a few more times and check for dirt or damage.
- On a laptop, turn on the laptop layout to hide the number pad.
What is key rollover (anti-ghosting)?
Key rollover is how many keys your keyboard can detect at the same time. Many cheap keyboards handle 2 to 6 keys at once. Gaming keyboards often support “N-key rollover” (NKRO), which means every key can be pressed together.
Ghosting is when a key you pressed does not show up, or a key you did not press appears, because too many keys are held. Hold combinations you use in games (for example W + A + Shift + Space) and check that all of them light up in blue.
Common keyboard problems
- Dead key: the key never lights up. Try cleaning under the keycap, or test with another USB port or cable.
- Stuck key: the key stays blue after you release it. Dirt or a damaged switch can cause this.
- Double typing (chatter): one press types two letters. This is often a worn mechanical switch.
- Wrong character: your system keyboard layout may not match your physical keyboard. Check the code shown above.
- Wireless lag: low battery or interference can cause missed key presses.
Frequently asked questions
Is this keyboard tester safe?
Yes. Everything runs in your browser. Your key presses are not saved or sent anywhere.
Why does a key not react?
The key may be broken, blocked by dirt, or captured by your system (like Fn or some shortcuts). Try another port, clean the key, or test on another computer.
How do I test for ghosting?
Hold several keys at the same time and watch the “Held now” number. If it stops increasing or keys do not light up, you have reached your keyboard’s rollover limit.
Does it work with any keyboard layout?
Yes. The picture uses a standard layout, but each key is detected by its physical position, so it works with QWERTY, AZERTY, QWERTZ and other layouts.