What determines the size of the circle of a curl?

The size of the circle of a curl is primarily determined by the tool diameter used during the curling process. This means that the larger the diameter of the curling tool, the larger the resulting curl will be. When hair is wrapped around a curling tool, the hair takes on the shape that corresponds to the tool's dimensions.

For instance, if a stylist uses a wide curling iron, the hair will curl into larger, looser waves, while a smaller curling tool will create tighter curls. Therefore, the tool diameter directly influences the shape and size of the curls created, making it the correct factor to consider when determining the curl size. Understanding this concept is essential for hairstylists as it enables them to select the appropriate tools to achieve their desired hairstyles effectively.