Test every key on your keyboard instantly with our free online Keyboard Tester, Key Checker, and N-Key Rollover Tool. Detect stuck keys, dead keys, ghosting, chatter, and verify anti-ghosting performance on mechanical keyboards, gaming keyboards, laptop keyboards, and membrane keyboards — all in your browser.
A Keyboard Tester (also called a Key Tester, Keyboard Checker, or Keyboard Test Tool) is an online diagnostic that verifies every key on your keyboard registers correctly with your computer. By pressing each key while watching a visual on-screen keyboard, you can instantly spot dead keys, stuck keys, ghosting issues, and N-key rollover limitations — all without installing any software.
Our free online Keyboard Tester works with mechanical keyboards, gaming keyboards, laptop keyboards, wireless keyboards, and membrane keyboards across Windows, macOS, Linux, and Chromebook. Whether you're testing a brand-new keyboard before the return window closes, diagnosing typing problems after a coffee spill, or verifying that your gaming keyboard actually supports the NKRO it advertises, this key checker gives you instant visual feedback for every single keystroke.
This tool is especially valuable for gamers (to test anti-ghosting), mechanical keyboard enthusiasts (to verify switch performance), IT administrators (to quickly diagnose office keyboards), and anyone buying a used keyboard (to catch hidden dead keys before paying).
A complete diagnostic toolkit for any keyboard — from basic membrane models to premium mechanical gaming boards.
Live on-screen keyboard highlights every pressed key in real time. Test all 104 keys individually to catch dead or stuck keys instantly.
Hold multiple keys simultaneously to test your keyboard's rollover. Verify 2KRO, 6KRO, or full NKRO claimed by manufacturers.
Press common gaming combos like W+A+Shift+Space to reveal ghosting — when key presses go missing in multi-key combinations.
Switch between Full 104-key, TKL (Tenkeyless), 75%, and 60% layouts to match your physical keyboard exactly.
Track keys tested, currently pressed, max simultaneous pressed, and total keystrokes in real time as you work through the test.
Rolling log of your last 30 keypresses with timestamps — perfect for debugging chatter (double-press) issues on old switches.
Everything runs locally in your browser. No keystrokes, no data, no metadata is ever sent to any server. Works fully offline.
Download a JSON report of test results — useful for warranty claims, RMA requests, or comparing multiple keyboards.
A complete keyboard diagnostic takes just a few minutes. Follow these steps for the most thorough inspection.
Click anywhere on the tool page first so your browser knows to send keystrokes here, not to another app in the background.
Choose the layout matching your physical keyboard — Full 104-key, TKL, 75%, or 60% — so the on-screen keys line up correctly.
Systematically work across every row, pressing each key. Orange = currently pressed, green = successfully tested and released.
Hold W+A+S+D+Space+Shift simultaneously. The "Currently Pressed" count should show all 6. Missing any = ghosting issue.
After pressing every key, any remaining dark (untested) key is likely dead or broken. Common culprits: Space, Enter, Fn keys.
Download your test results as a JSON file for warranty claims, RMAs, or detailed comparison between multiple keyboards.
Our online Keyboard Tester uses the browser's native keydown and keyup events — the same low-level signals that every text editor, game, and application uses. When you press a key, your keyboard's internal controller sends a signal to the operating system, which passes it to your browser, which fires an event our tool listens for. The matching visual key lights up in real time.
Every detected key captures its KeyboardEvent.code value — a hardware-level identifier that's independent of your keyboard language or layout. This means the tester works identically for QWERTY, AZERTY, QWERTZ, and Dvorak users. The physical switch position is what matters, not the character it types.
For N-Key Rollover testing, the tool maintains a live set of currently-held keys. Each time a new key is pressed, it's added to the set; each time one is released, it's removed. The size of the set at any moment is how many simultaneous keys your keyboard is reporting. If you physically press 6 keys but the counter only shows 4, you've found your rollover limit or ghosting threshold.
Because every measurement happens locally in JavaScript, nothing ever leaves your browser. No keystrokes are logged, transmitted, or stored on any server. Disconnect from the internet after the page loads and every feature will continue working perfectly.
Key rollover is the single most important specification for gaming keyboards. Here's what each rollover level means and who needs which.
| Rollover Type | Simultaneous Keys | Best For | Rating |
|---|---|---|---|
| 2KRO | Only 2 keys at once | Basic office typing, legacy USB keyboards | LIMITED |
| 3KRO | 3 keys reliably | Budget USB keyboards, entry-level | LIMITED |
| 6KRO | Any 6 keys + modifiers | Standard gaming, most tasks, USB HID spec | GOOD |
| 10KRO | 10 keys simultaneously | Competitive gaming, music production | GREAT |
| NKRO | Every key on keyboard | Esports, stenography, professional use | BEST |
The most common keyboard problems and exactly how to identify each using our visual diagnostic tool.
A key that never registers when pressed. Shows as permanently dark in our tester. Caused by broken switches, damaged circuit traces, or liquid damage. Usually requires switch replacement or full keyboard replacement.
A key that registers continuously without being physically held. Shows as permanently orange in our tester. Often caused by debris under the keycap, damaged stabilizer, or sticky switch spring.
A single press registers as two or more presses. Visible in our keystroke history log as rapid repeats. Typically caused by worn switch contacts on aging mechanical keyboards — replacement switch fixes it.
Some keys fail to register when pressed with others. Visible when your "Currently Pressed" count is less than the keys you're physically holding. Only fixable by buying a keyboard with better rollover.
A key that works sometimes but fails unpredictably. Often shows successful test then fails on repeat press. Indicates failing switch, loose solder joint, or worn contact on membrane.
Shift, Ctrl, Alt, or Cmd keys getting stuck or missing. Can make typing nearly impossible since every character becomes modified. Test each modifier individually in our tool.
A free online key tester is genuinely useful for more people than you'd expect.
Verify NKRO and anti-ghosting on gaming keyboards. Essential for FPS, MOBA, fighting games where multiple keys fire at once.
Test new switches, diagnose chatter on aging boards, and verify custom builds before finalizing a mechanical keyboard project.
Batch-test dozens of office keyboards quickly. What used to be an hours-long task becomes minutes with visual confirmation.
Before paying for a used or refurbished keyboard, test every key. Dead keys are the #1 hidden defect sellers don't disclose.
Diagnose typing issues after coffee spills, drops, or wear. Confirms whether problems are hardware (keyboard dead) or software (driver/OS).
Quick check after keyboard cleaning or troubleshooting stuck keys. No IT ticket needed — verify in seconds yourself.
Ensure punctuation and symbol keys work perfectly before starting important work. Missing semicolons in code cause real bugs.
Verify keyboard shortcuts work reliably in DAWs. Shortcut-heavy workflows demand proper modifier handling and rollover.
Quick answers to the most common questions about testing keyboards, rollover, ghosting, and keyboard diagnostics.