Circularity Error: What's a Good Value?

You ran a controller test, saw "circularity error: 9%," and immediately wondered whether your controller is broken. It almost certainly isn't. In fact, if your controller reported 0%, that would be more concerning than 9%.

Circularity error is one of the most misunderstood metrics in controller testing, largely because the word "error" implies something is wrong. It isn't a fault reading. It's a description of your stick's physical shape, and the "ideal" value is not zero.

Here's what the number actually measures, what's normal, and when a reading genuinely indicates a problem.

What circularity error measures

When you rotate an analog stick all the way around its outer edge, the path it traces gets plotted as a shape. In a purely geometric world, that shape would be a perfect circle.

Real sticks are mechanical assemblies of plastic and metal moving inside a physical housing, and they don't trace mathematically perfect circles. Circularity error is simply the deviation between the shape your stick actually traces and a perfect circle, expressed as a percentage.

Critically, this measures your stick's outer range, not its centre. That distinction matters more than anything else in this article, because it's what separates circularity from drift.

Drift is what happens at the centre: your stick reports movement when it's resting untouched. That's a fault, and it gets worse over time.

Circularity is what happens at the edge: how evenly your stick reaches its full range in every direction. That's largely a design characteristic, and it's mostly fixed from the factory.

You can have a controller with terrible circularity and zero drift, or perfect circularity and severe drift. They're independent measurements describing different parts of the stick's behaviour, which is why testing tools report them separately.

What's a good circularity error?

Here's the practical answer, and it surprises most people.

Stock controllers from Sony and Microsoft typically measure somewhere around 6% to 9%, and repair specialists who recalibrate sticks professionally often deliberately target roughly 7% to 9% as an optimum rather than chasing lower numbers.

Broadly, the ranges break down like this:

0% to 5%: A near-perfect circle. Sometimes indicates high-quality calibration or Hall effect sensors, but as explained below, a suspiciously low number can also mean software is manipulating the reading.

6% to 15%: Normal. This is where the overwhelming majority of console controllers sit, including brand new ones straight from the box.

20% and above: Worth investigating. The stick is likely restricted and can't reach the full corners or edges of its range, which does affect gameplay.

So if your reading landed in single digits or low teens, your controller is behaving exactly as designed.

Why 0% is a warning sign, not a target

This is the counterintuitive part, and it's the most useful thing to understand about this metric.

Some controllers, particularly certain third-party models, advertise remarkably low circularity error, sometimes fractions of a percent. That looks impressive on a graph. In practice, it's often produced by a software technique sometimes called cardinal snapping, where the controller's firmware forces your input to snap toward the cardinal directions (straight up, down, left, right) rather than reporting exactly where your thumb put the stick.

That produces a beautiful, geometrically clean plot. It also feels bad to play with, because the moment you try to make a tiny adjustment, aiming at someone's head, easing into a corner, the software fights you and pulls your input toward the nearest clean direction.

A small amount of natural, honest error, in the low single digits and upward, generally feels smoother to a human thumb than a robotically perfect reading produced by firmware overriding your actual input.

The lesson: don't shop for a controller by its circularity number, and don't try to "fix" a normal reading. A raw, unfiltered reading of 8% from a PS5 or Xbox controller is more trustworthy than a filtered 0.1% from a controller whose firmware is quietly editing your inputs.

Why a "squarish" shape isn't broken

The second common panic is seeing a trace that looks like a rounded square rather than a circle, producing a high error percentage.

This is frequently intentional. The physical gate, the housing that limits how far the stick travels, can be shaped closer to a square, and that has a real gameplay purpose: it lets you reach maximum input faster, particularly on the diagonals, without pushing the stick right to the extreme edge.

For fast shooters, that's an advantage. Reaching 100% input quickly is exactly what you want when you need to sprint or turn instantly. A perfectly circular gate requires you to push further to hit full speed in the diagonal directions.

Some fighting pads and older controllers use pronounced physical square gates, and those will report large error percentages simply because the plastic shell physically prevents a circular motion. Nothing is wrong with them.

So before concluding your controller is faulty, look at the shape of the trace, not just the number. A clean, even, slightly squarish shape is fine. What matters is whether the shape is symmetrical and whether it reaches full range in every direction.

When circularity error does indicate a problem

There are genuine faults this test reveals, and they show up as shape problems rather than as a high number alone.

Flat spots. If one section of the trace is visibly flattened or clipped while the rest is fine, the stick isn't reaching full range in that direction. This often points to mechanical wear or a limitation in the potentiometer, and it's the clearest sign of a real issue.

Asymmetry between quadrants. If the error is concentrated in one direction- up-left is fine, but down-right is restricted- that uneven wear pattern suggests a mechanical problem rather than a design characteristic.

A big difference between your two sticks. Left and right sticks wear at different rates, and the right stick usually wears faster because aiming demands more movement. A right stick that's markedly worse than the left points to usage-based wear.

Not reaching full range at all. If the stick can't hit its maximum in any direction, that has direct gameplay consequences. In Rocket League, certain manoeuvres require the stick's range to extend properly. In shooters with auto-sprint, a stick that can't reach full deflection may never trigger sprint at all, which players often misdiagnose as a game bug.

A sudden change. If your controller measured 8% six months ago and measures 22% now, the change is the signal, not the absolute value.

How to test circularity properly

Method matters here, because a sloppy test produces a meaningless result.

Connect the controller, ideally by USB for a clean baseline, and open the joystick calibration tool in a browser. Press a button first so the browser registers the gamepad.

Then push the stick fully to its physical outer edge and rotate it slowly and steadily all the way around, completing at least two full revolutions. Slowly is important. A fast, random wiggle produces a sparse, jagged trace that will look far worse than your stick actually is. You're tracing the outer gate deliberately, not shaking the stick.

Test one stick at a time and keep the results separate, since comparing them is a large part of the diagnostic value.

Retest if the trace looks sparse, clipped, or wildly different from how the controller feels in games, because an unrepresentative sample is the most common reason for an alarming reading. It's also worth retesting after changing connection type, updating firmware, or altering Steam Input or vendor software settings, since all of those can affect what the browser sees. For a deeper dive on doing this rigorously, our professional calibration methods guide covers the process in detail.

Does the sensor type matter?

Somewhat. Hall effect and TMR sticks, which sense position magnetically with no physical contact, tend to show smoother, rounder traces than worn potentiometer sticks, mostly because they don't develop the mechanical wear that creates flat spots over time. Our Hall effect vs traditional analog sticks comparison explains the underlying difference.

But sensor type doesn't determine gate shape. A Hall effect controller with a squarish physical gate will still report a squarish trace, because the gate is a plastic housing, not a sensor characteristic. The two things are independent.

Can you fix or improve circularity?

Mostly, you manage it rather than fix it.

Minor circularity irregularities can often be compensated for with in-game sensitivity curves and deadzone settings, and honestly, most players will never notice a normal amount. If your reading is in the normal range, the right action is to leave it alone. Our Rocket League deadzone guide covers tuning for a game where full stick range genuinely matters.

Some tools and vendor software allow recalibrating a stick's range, which can adjust the reported circularity. Be cautious here: recalibrating to chase a lower number can reduce your usable range, and if in-game settings were tuned around your original behaviour, they may need readjusting afterward.

Severe circularity problems, genuine flat spots, badly restricted range, or a stick that can't reach its corners, usually mean mechanical wear, and the fix is replacing the stick module rather than adjusting software.

The short version

Circularity error describes the shape your stick traces at its outer edge compared to a perfect circle, and it's a design characteristic far more than a fault reading. Stock PS5 and Xbox controllers typically sit around 6% to 9%, and specialists often target 7% to 9% deliberately. A 0% reading is more often a sign of firmware manipulating your input than of a superior controller, and a squarish trace is frequently intentional tuning for faster diagonal response. What actually indicates a problem is shape rather than the raw number: flat spots, asymmetry between quadrants or between your two sticks, an inability to reach full range, or a sudden change from a previous reading.