Stick circularity error explained

What circularity error means

Push a thumbstick to its edge and rotate it. Ideally, the controller reports full travel in every direction, so the path it draws is a perfect circle. In practice the path is rarely perfect. Some directions fall short of the edge, and others, usually the diagonals, overshoot it.

slices of 5° around the circle

72

of the circle must be traced before an error shows

90%

a stick that reaches the circle exactly in every slice

0%

Circularity error is the average gap between that path and the ideal circle, as a percentage of full travel. The stick circularity test splits the circle into 5° slices, keeps the furthest point you reach in each, and averages how far those points sit from the circle. A stick that reaches the circle evenly all the way round reads close to 0%.

It matters because the stick's output is what the game sees. If a stick can't reach full travel at some angles, you can't run or turn at full speed in those directions. If it overshoots on the diagonals, diagonal movement can feel faster or jumpier than straight lines.

How to run a joystick circularity test

1. Connect your controller by USB or Bluetooth and open the stick circularity test.
2. Press any button so the browser detects the controller. If you have more than one connected, choose it under Select controller.
3. Push the left stick all the way to its edge and rotate it slowly through two or three full circles. Keep steady pressure against the edge.
4. Watch the percentage of circle traced under Avg error. The error appears once at least 90% of the circle has been covered.
5. Let go of the stick and wait a moment. Offset at rest shows how far from centre it settles.
6. Repeat with the right stick. Press Reset to clear both and measure again.

Rotate slowly. Spinning the stick fast can skip slices and give a less accurate trace. Run the test two or three times and compare: a single unusual result is often down to technique.

What's a good circularity result?

Lower is better, and the figures people commonly report fall into rough bands. Single-digit errors are generally seen as good. Figures in the low teens are common on many stock controllers and usually aren't noticeable in games. Results well above that are more likely to be felt.

Treat these as rough guides, not pass or fail limits. Different testers measure in different ways, so a number from one tool won't match another exactly. What matters most is comparing your two sticks, and comparing the same stick over time.

Look at the shape on the canvas as well as the number. A trace that's flat on one side, or dented in one direction, points to a stick that can't reach full travel there. A trace that pokes out evenly at all four diagonals is a different story, covered next.

Why square gates and diagonals read higher

The gate is the opening around the stick's base that limits how far it can move. Most modern controllers have a round gate. Some, including many older and retro-style controllers, have a square or octagonal gate, which lets the stick travel further on the diagonals.

A square-gated stick will always look like a rounded square on the trace and read a higher circularity error. That's how it's built, not a fault. Some controllers and drivers also scale the output outwards so the stick hits full value before it reaches the gate, which pushes the diagonals past the circle too. A high error with an even, symmetrical shape is usually one of these.

Deadzone vs drift vs circularity

These three get mixed up, but they measure different things.

A stick can have a perfect circle and still drift, or rest at zero and still have a poor circle. Check both. For drift specifically, our stick drift guide walks through the fixes.

How to improve stick circularity

• Clean the stick. Dust and grime around the base can stop it reaching the edge smoothly. Compressed air around the base, with the stick pushed in each direction, is free and often helps.
• Calibrate it. Some platforms and controllers have a calibration step, such as the Switch's stick calibration in System Settings. On Windows, Steam Input includes stick calibration and outer deadzone options in a controller's settings.
• Adjust the deadzones. If a game or Steam Input lets you set an outer deadzone, a small increase can make a stick that falls slightly short reach full value in every direction. Too much flattens fine control near the edge.
• Update the firmware. Controller firmware updates can change how stick values are read and scaled.
• Replace the stick. Worn sticks often lose travel in one direction. Replacement modules, including Hall effect sticks that measure position with magnets instead of wearing contacts, are available for many controllers.

After each change, press Reset in the stick circularity test and trace the stick again to see whether the number and shape improved.

Is a high circularity error worth fixing?

Often not. If the shape is even and the error is similar on both sticks, it's probably the controller's design and you won't notice it in games. It's worth acting on when one stick reads much higher than the other, when the trace has a clear flat or dented side, or when you can feel that one direction is slower than the rest in a game.

If the error has grown over time, that's a sign of wear. Write down both sticks' results each time you test so you have something to compare against later.

Next, check the rest of your controller

Circularity only covers the sticks. Check every button and trigger in the gamepad test, then fire each rumble motor in the controller vibration test. If rumble isn't working, see our guide to controller vibration problems.