A tool capable of creating and measuring circles and circular profiles of any size without the need for a pivoting center arm. Circle size can be selectively adjusted and held, and both the inside and outside of tool creates and measures circles of a near infinite number of size. The tool contains marking rules such as radius, diameter, arc length, circumference, sector area, area of a circle for any size circle, etc., obviating the need for calculating the same, and any or a combination of unit measure systems can be employed.