Sharpen the pencil. Before inserting the pencil in the compass, sharpen it with a handheld pencil sharpener. Sharpen the pencil until there is at least 1/4-inch of exposed lead. Wipe the lead tip off with a cotton rag to remove any debris.
Close the compass. Close the compass so its two arms are parallel with one another. The span of the compass is adjusted with either a wheel that rides on a threaded post between the two arms or a hinge at the top of the compass. Position the compass arms next to one another in order to align the pencil with the point of the compass.
Insert the pencil. The pencil is held in place by either a metal clamp or a post that screws into the side of the pencil. Place the pencil in the pencil mount. The pencil mount is attached to one of the compass arms. Place the compass on a surface, point down. Lower the pencil through the mounting hole until its lead touches the surface. Tighten the clamp or post that holds the pencil in place.
Determine the radius of the circle you want to draw. The radius is the distance from the center of the circle to its outer edge. If a 6-inch circle is being drawn, the radius will be 3 inches. The radius will always be half of a circle's diameter.
Draw a radius line to adjust the compass. Draw a straight line on a piece of paper. Mark a point on the line. Using a ruler, mark the second point to determine the circle's radius. If the circle is 6 inches in diameter, the distance between the two points on the line should be 3 inches. Many compasses will have a scale you can use to determine the radius of the circle you want to draw; draw the compass arms apart until the pointer on the scale reaches the desired radius length.
Adjust the compass. Place the metal point of the compass on one of the line's points. Spread the compass's arms out until the tip of the pencil lead sits on the second point.
Draw the circle. Check the radius once more by positioning the points of the compass on the points of the drawn line. Place the metal tip on the drawing surface. Turn the top of the compass with the thumb and index finger, slightly applying pressure to the compass to ensure a clean line.