Proportional compasses used in copying drawings on a given larger or smaller scale. The Livot of compasses is secured in a slide which is adjustable in the longitudinal slots of legs, and capable of being secured by a set screw, the dimensions are taken between one pair of points and transferred with the other pair, and thus enlarged or diminished in proportion to the relative distances of the points from the pivot. A scale is provided on one or both legs to indicate the proportion.