Joystick Circularity Test
Rotate a stick around its outer edge several times. The page plots the path and describes radial consistency and angular coverage without pretending there is one universal “good” circularity score.
Circularity / outer-edge trace
Connect a controller and start the trace.
Trace summary
No trace yet.
Controller firmware, operating-system mappings and browser normalization can transform stick values. Compare repeated tests and left/right behavior rather than treating one number as a universal hardware grade.
What these measurements mean
Angular coverage shows how much of the full 360° path the trace reached. A complete, deliberate rotation should approach 100%.
Mean outer radius is the average browser-observed distance from center while the stick was near its outer edge. It is mainly useful for repeated runs and left/right comparisons; values can exceed 1.000 near diagonals because the browser exposes X and Y axes separately.
Radial variation describes how much the outer-edge radius changed while you rotated the stick. Lower and more repeatable variation generally means a more consistent trace, but there is no universal pass/fail number for every controller.
Trace samples is the number of browser observations recorded during the test. It indicates how much input data the summary was calculated from.