Measurement Methods and Limits
The tools observe browser input events or calculate from values you enter. This page explains how to repeat a check and what it cannot establish. It is a method description, not a published hardware benchmark dataset.
Repeat a DPI estimate
- Record the mouse/profile, OS pointer speed and acceleration setting, display scaling, browser version and zoom.
- After the page fully loads, the tester defaults to 1 inch. Manually choose and mark a shorter distance, such as 0.2 inch, if pointer travel will not fit inside the track.
- Select the unit and enter the distance you marked. Switching units does not convert the number: re-enter the measured distance in the newly selected unit before starting. Hold the physical left mouse button inside the track, move horizontally in one direction to the mark, then release inside it.
- The tester rejects reversed drags, leaving the track, lost button contact and window or page interruptions. Changing distance or units also cancels a run. Release the button and start a fresh drag after a rejection. Manually discard a run if you lift the mouse or miss a physical mark; the browser cannot detect those mistakes. Escape is not a cancellation control.
- Repeat under unchanged conditions and record the spread, not just the most appealing value.
The calculation divides one-way horizontal browser cursor travel inside the track by physical inches. Reversing direction rejects the run rather than adding extra travel. It does not read raw sensor counts. OS acceleration, display scaling and browser zoom can affect the result, so a stable estimate is not proof of hardware DPI accuracy.
Other input checks
Polling tests observe events delivered to the browser, not every USB report or total click latency. Click and key tests can reveal a repeatable symptom, but event timing alone cannot diagnose a defective switch. Reproduce a problem in another application before drawing a hardware conclusion.
What a measured comparison needs
Record the mouse/model, firmware if known, connection, OS/browser versions, configuration, distance reference, individual runs and uncertainty. Label simulated checks and illustrative arithmetic separately from physical measurements. No universal error tolerance is claimed here.