Up milling is also referred to as conventional milling. The direction of the cutter rotation opposes the feed motion. For example, if the cutter rotates clockwise , the workpiece is fed to the right in up milling.

Down milling is also referred to as climb milling. The direction of cutter rotation is same as the feed, if motion. For example the cutter rotates counterclockwise , the workpiece is fed to the right in down milling.