What KeyBench checks
| Device | What it finds |
|---|---|
| Keyboard | keys that never register; keys that fire twice (two presses less than 60 ms apart); keys held for more than 3 seconds, a sign of sticking; how many keys are recognised at once (rollover) |
| Mouse | all five buttons; accidental double-clicks with a threshold of 60, 80 or 120 ms; wheel up, down and sideways, and scroll steps in the wrong direction; polling rate |
| Gamepad | every button and trigger; the axes; stick drift; how round the stick’s range is (circularity error); vibration of the light and heavy motors and of the triggers |
Keyboards are shown as full-size, TKL (without the number pad) or laptop layouts, in ANSI or ISO shape. Key labels follow your actual layout where the browser allows it. Gamepad buttons are labelled for Xbox, PlayStation and Switch Pro controllers.
How to test a keyboard
- Open KeyBench on the Keyboard tab and choose the layout that looks like yours.
- Press every key once. Keys that worked turn coloured on the picture; the ones still blank have not registered yet.
- Press the suspicious keys several times, quickly. If a key registers twice for one press, it is counted as a double fire, the classic sign of a worn switch.
- For rollover, hold down as many keys as you can at once, for example a whole row. The counter shows the largest number recognised together. Many office keyboards stop at 2–6 keys in some combinations; gaming keyboards usually report all of them (N-key rollover).
- Check the report at the bottom: it lists the keys not pressed yet, double fires, keys held too long and the rollover.
Some keys never reach any web page: Fn is handled by the keyboard itself, and the system may take Win, Alt+Tab, Print Screen and media keys. In Chrome and Edge the Full screen: catch Esc and Win button lets KeyBench catch more of them.
How to test a mouse
- Switch to the Mouse tab and click inside the test area with each button: left, right, middle and the two side buttons.
- Click the left button steadily for 20–30 seconds, one click at a time. Any accidental double-click is counted. Start with the 80 ms threshold; 60 ms is stricter, 120 ms catches slower bounces.
- Scroll the wheel slowly in one direction. Steps registered in the opposite direction mean a worn wheel encoder.
- Move the mouse in quick circles to measure the polling rate. Typical values are 125 Hz for office mice, 500–1000 Hz for gaming mice, and higher for some new models.
How to test a gamepad and stick drift
- Connect the controller by cable or Bluetooth and press any button: browsers show a gamepad only after the first press.
- On the Gamepad tab, press every button and pull both triggers all the way. Analogue values are shown from 0 to 1.
- Let go of both sticks for 3 seconds. KeyBench measures how far they stay from the centre: under 0.05 is normal, under 0.12 is light drift, more than that is drift you will notice in games.
- Rotate each stick slowly around its full edge a few times to measure the circularity error. A large error means the stick does not reach the corners evenly.
- Try the vibration buttons. Trigger rumble works only on controllers that have it, such as the Xbox Series controllers in browsers that support it.
Privacy and sharing
KeyBench uses only standard browser events. Nothing you press is sent anywhere, and the page makes no outside requests. A shared link contains only the summary: how many keys were checked, the codes of keys not pressed, double fires, rollover, polling rate, click and wheel counters, the gamepad name, drift and circularity. Whatever you typed is not included. You can also save the report as a picture, text, JSON or PDF, or keep it in the history on this device.
Frequently asked questions
A key does not light up. Is it broken?
Not necessarily. Check that it is not Fn or a media key taken by the system, try another browser, and test the keyboard on another computer. If the key fails everywhere, the switch or its contact is faulty.
How do I fix a mouse that double-clicks?
The cause is almost always a worn micro-switch. It can be replaced, the warranty may cover it, and some mice have a debounce setting in their software that hides the problem.
What is a good polling rate?
125 Hz is fine for office work. For games, 500–1000 Hz feels smoother. The measured value can be a little below the nominal one, and some browsers limit it.
Can I fix stick drift?
Mild drift can often be hidden with a larger dead zone in the game or system settings. Strong or growing drift means a worn stick module, which needs repair or replacement.
Does KeyBench work on a phone?
Yes, with a Bluetooth or USB keyboard, mouse or gamepad connected to the phone or tablet.