Stick Circularity Test

Measure joystick accuracy by tracing the rim. Detect quadrant weakness, gate wear and coverage gaps.

Circularity (left stick)

Waiting

Slowly rotate the left stick around its rim 3 full turns. A perfect stick traces a circle; deviations show quadrant weakness or gate wear.

Samples

Max radius

0.000

Min radius

Deviation

Overview

What the Stick Circularity Test does

A healthy analog stick traces a near-perfect circle at full deflection. Worn potentiometers, damaged gates, or weak springs produce a flat spot, an oval, or a spiral. This test plots your stick trace against a perfect circle so you can see deviations directly and get a percentage error you can act on.

Steps

How to run the test

Push the stick fully to one edge and hold it there.
Slowly rotate around the rim, keeping full deflection, for at least three full turns.
Watch the trace fill in a shape around the reference circle.
Read the deviation percentage. Under 5% is excellent, 5 to 15% is worn but usable, over 15% points to a physical fault.

Why circularity matters more than drift for aim

Drift is a resting offset. Circularity error is a moving offset. If your stick pulls a perfect circle when you rotate it, every angle reports the same magnitude and your character turns at a steady speed. If the trace is oval or has flat spots, you lose speed at certain angles and gain it at others. In a shooter this feels like your aim snapping when you cross a specific direction, or slowing down on diagonals. It is one of the top complaints from players convinced their controller is fine on the drift test.

How to read the trace shape

A perfect stick draws a solid ring exactly on the reference circle. An oval means the X and Y ranges are unequal, typically from asymmetric potentiometer wear. A flat spot is a section that never reaches full deflection, usually from a broken gate or a stick that hits a physical obstruction inside the shell. A spiral means the stick loses range as it rotates, pointing to a spring problem or a physically loose module. Each shape tells you what to fix.

How the percentage is calculated

The tester compares your trace radius to the unit circle radius at every sampled angle and averages the error. Under 5% is competitive-grade and matches what a new hall-effect stick produces. Between 5% and 15% is typical for a used pad and playable in casual games. Above 15% and you should not be trying to grind ranked matches with that stick. This is the same measurement gamepad reviewers use to score analog quality.

Fixes for common circularity problems

For flat spots, remove any thumbstick topper you have added. Aftermarket toppers can bind against the shell at extreme angles and produce a flat spot that disappears the moment you remove them. For oval traces, run the calibration on your platform, then re-test. If the oval remains, the stick is worn. For spiral traces, the stick module has failed mechanically and cannot be recalibrated back to good.

How this test connects to other diagnostics

Run this alongside the Stick Drift Test to distinguish resting drift from moving accuracy. Sticks can pass drift and fail circularity, or the other way around, and each condition needs a different fix. If both fail, replace the module or swap to a hall-effect controller and re-run both tests to confirm the fix worked.

Fix it

Common problems and quick fixes

Aim slows down when moving diagonally

Flat spot at 45 degrees. Trace the rim slowly and watch for gaps. Replace the stick or remove any thumbstick extender.

Turning speed changes as I rotate the stick

Oval trace. Recalibrate first. If it persists, the potentiometers are unevenly worn.

Full-circle trace shows a spiral inward

Return spring is weakening. Replace the module. This will get worse quickly.

FAQ

Common questions

What causes flat spots?+

A worn potentiometer track in one direction, a broken gate, or a weak return spring in that quadrant.

Left stick fine, right stick bad?+

Sticks fail independently. It is common for one stick to wear out first, especially the left on shooters and the right on racing games.

Does circularity affect aim?+

Yes. If your right stick cannot reach full deflection in a diagonal, your aim slows or drops out completely at that angle. It is often mistaken for stick drift by feel.

Rotate the rim three times and see the exact percentage your stick is off. If you play shooters or racing games, this test tells you if you are losing kills to your hardware.

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Related diagnostics

Pair this test with any of the below for a full controller health check.

Analog