Keyboard Tester

How to test your keyboard

1. Press every key once. Each key turns blue when it registers, so any key that stays grey is not being detected.
2. Hold several keys together, for example A, S, D, F, J, K and L, to check rollover.
3. Press a key quickly several times to check for double-presses, where one tap registers as two.
4. Run the polling rate and input delay tests if you want to compare your keyboard's speed. Both are estimates.

The tester works with full-size, tenkeyless (TKL), 75% and 60% keyboards. Pick your layout (ANSI or ISO) and your operating system (Windows or Mac) so the key labels match your keyboard.

What each test checks

• Last key shows the key you just pressed, so you can match it to the physical key.
• Rollover checks how many keys can be held at once before one stops registering.
• Double-press check flags a key that registers a second press too soon after release, a common sign of a worn switch.
• Polling rate estimates how often the keyboard reports to the computer.
• Input delay estimates the time from a key press to the next screen update.
• Reaction time measures how quickly you respond to a prompt.

When this tool helps

• A key sometimes types twice or not at all. Use the double-press check to see whether the switch is wearing out.
• A new keyboard seems slow or laggy. Compare its polling rate and input delay with your expectations.
• You want to confirm that a keyboard is working before returning it.

Limits of a browser test

• The Fn key is handled inside the keyboard and is never sent to the computer, so no website can test it. Test it by using it, for example Fn plus a brightness key.
• Print Screen and some laptop special keys may be taken by the computer before the browser sees them.
• A browser can measure polling rates only up to about 2000 Hz, so a 4000 Hz or 8000 Hz keyboard will read lower than its real rate.
• On a phone or tablet, connect a physical keyboard first.

Frequently asked questions