Stick range diagnostics

Circularity Test

Rotate an analog stick around its edge and this circularity test will trace range, radius, and error against an ideal circular path.

Circularity Error Scope

Rotate a stick around the gate to compare its path against an ideal circle.

No Controller Detected

Connect via USB or Bluetooth, then press any controller button to activate detection.

Current radius

0.000

A full edge sweep should approach 1.000 without flat spots.

Circularity score

0.0%

Higher is closer to a smooth circular gate.

Current error

100.0%

Browser readings vary by mapping and controller firmware.

Embed This Tool

Use this iframe code to place this exact diagnostic widget on another page.

Circularity widget

Embed the circularity trace for analog stick edge travel checks.

https://gamepadtesteronline.org/embed/circularity-test/

<iframe src="https://gamepadtesteronline.org/embed/circularity-test/" title="Circularity widget" width="100%" height="560" loading="lazy"></iframe>

Why Circularity Matters

A circularity test looks at the shape of analog stick travel instead of only checking center drift. Many sticks can rest near zero but still clip corners, flatten one side, or fail to reach a consistent edge. This circularity test plots the stick path against an ideal circle so uneven movement becomes visible while you rotate the stick around the gate.

A good stick circularity test helps with aiming, camera control, racing menus, and any game that expects smooth diagonal input. If a stick reaches full value on the horizontal axis but falls short on diagonals, diagonal movement can feel slower. If the path forms a square, the controller or driver may be clamping values. The joystick tester exposes those patterns without requiring a game engine overlay.

The score on this page is a practical browser estimate. It compares current radius against the expected outer range and shows the trace history. It does not replace hardware calibration equipment, but it does make range problems easier to discuss, screenshot, and compare before and after cleaning or configuration changes.

Running A Clean Stick Circularity Test

Move the stick to the outer edge, then rotate slowly around the gate. A clean circularity test needs deliberate movement; quick snaps can skip parts of the trace and exaggerate gaps. Try one clockwise pass and one counterclockwise pass. If both passes show the same flat side or missing corner, the issue is more likely physical or firmware-related.

Do not judge circularity while the stick is still near center. The trace is most meaningful near the outer ring, where full-range movement should occur. If the stick cannot approach the outer ring in one direction, compare USB and Bluetooth, then run the stick drift test to see whether center offset is also present.

Some controllers intentionally shape stick output for compatibility. That means a circularity test can reveal square clipping even when the controller feels acceptable in many games. Use the result as a clue, not a verdict. The best next step depends on whether the game allows calibration curves, deadzone changes, or raw input mode.

Reading Radius, Error, And Trace Shape

The radius value shows how far the current stick position is from center. Near the outer gate, a radius close to one is expected. The circularity error compares that radius to the ideal outer circle. Repeated high error on one side points to uneven travel, while high error everywhere can mean the browser mapping or controller firmware is scaling the stick range.

Look at the trace shape before focusing on the score. A smooth oval may be less disruptive than a sudden notch. A trace that jitters wildly can point to noisy sensors or wireless issues. A trace that stops short on one diagonal can explain why movement feels weak in one direction. The joystick tester view is intentionally visual because the path tells the story.

After a circularity test, move to mapping if the wrong axis appears, drift if center is unstable, or calibration if you need a structured center and deadzone workflow. Keeping these tests separate avoids overloading one page and makes each controller diagnostic easier to interpret.

Diagnostic Glossary

Outer ring

The expected full stick range near the physical gate edge.

Circularity error

A practical estimate of how far the current radius differs from the ideal path.

Clipping

A flattened or squared input path caused by scaling, firmware, or limited travel.

Questions Users Ask

Short answers for common diagnostic decisions on this page.

Is a perfect circularity score required?

No. Many controllers are not perfectly circular. Look for obvious flat spots, missing corners, and changes that affect play.

Which stick should I test first?

Test the stick that affects your symptom first, then compare the other stick as a control.

Why does the trace look square?

The controller or driver may be clamping stick values. Some games handle this better than others.

Useful Next Checks

Run a stick drift test

Check idle offset and deadzone before changing in-game sensitivity.

Review calibration

Estimate center offset, range behavior, and practical deadzone choices.

Inspect button mapping

Confirm indexes, labels, analog values, and unusual layouts.

Read troubleshooting paths

Fix detection, Bluetooth, permission, browser, and mobile issues.