Keyboard Rollover Test
Observe simultaneous key reporting for free and guided combinations. Reports only keys the browser receives.
Tests run locally in your browser. We do not upload keystrokes, pointer paths, or media.
Important
- Only keys that reach the browser are counted. OS shortcuts may intercept combinations.
Hold any combination. Only keys the browser receives are shown.
Currently pressed
None
Results
- Free max simultaneous
- 0
- Pressed now
- 0
- Guided complete / incomplete
- 0 / 0
- Events
- 0
Possible missing only means the browser did not report those codes during the hold — not NKRO certification or hardware failure.
How to use
- Open this tool and follow the on-screen Start control.
- Keep the tab focused during measurement for accurate samples.
- Review results, limitations, and related tools below.
- Use Reset to clear local trial state when available.
What the result means
- Numbers come from browser APIs and local timing only.
- See Limitations for what this test cannot claim.
Limitations
- Only keys that reach the browser are counted. OS shortcuts may intercept combinations.
Troubleshooting
- Nothing happens after Start
- Focus the tab, allow required permissions if prompted, and ensure the test surface receives input.
Related tools
Keyboard Tester
Press keys to verify browser keydown and keyup events across Windows, Mac, compact, and full-size layouts.
Keyboard Event Rate Test
Measure browser-observed keyboard event rates while you tap. Not a USB analyzer or hardware polling certification.
Keyboard Double-Press Test
Analyze possible duplicate key press cycles from browser keydown/keyup timing. Not a switch autopsy.
FAQ
Is this a hardware laboratory result?
No. DeviceMetrik reports browser-observed values with explicit limitations.