Circularity is a measure of how close a given curve is to being perfectly circular, while cylindricity is a measure of how close a given cylinder is to being perfectly round. In other words, circularity measures the deviation from perfect roundness in two dimensions, while cylindricity measures the deviation from perfect roundness in three dimensions.

## What is circularity?

Circularity is a measure of how close a curve is to being a perfect circle.

Circularity can be quantified by calculating the ratio of the circumference of the curve to its diameter. The closer this ratio is to 1, the more circular the curve is. A value less than 1 indicates an elliptical shape, while a value greater than 1 indicates a lobed or multi-lobed shape.

## What is cylindricity?

Cylindricity is a measure of how close a surface is to being a perfect cylinder.

Cylindricity, on the other hand, is quantified by calculating the ratio of the height of the cylinder to its diameter. The closer this ratio is to 1, the more cylindrical the surface is. A value less than 1 indicates a frustum (truncated cone) shape, while a value greater than 1 indicates a pyramid shape.

Cylindricity is an important quality control measurement for many types of cylindrical parts and components. It checks for how closely the surface of a cylindrical object deviates from being perfectly round. Cylindricity measurements are typically made with a special type of measurement tool called a cylindrical gauge.

## Circularity Vs. cylindricity – The key difference

Circularity is a perfect circle, while cylindricity is an imperfect circle. The difference between these two types of circularity is the amount of distortion in the shape. Cylindricity is more distorted than circularity, meaning that it is not a perfect circle.

## How to measure circularity and cylindricity

To measure circularity, you will need a caliper. Place the caliper on the object so that the jaws are touching the sides of the object at two points that are directly across from each other. For cylindricity, you will also need a caliper. Place one jaw of the caliper on the side of the object and the other jaw on top of the object.

Photo by ROMBO: https://www.pexels.com/photo/measuring-guitar-pick-3988555/