Drawer Slide Mount Type
Decide whether you want a side-mount, center mount or undermount slides. The amount of space between your drawer box and the cabinet opening will affect your decision.

Side-mount slides are sold in pairs or sets, with a slide attaching to each side of the drawer. Available with either a ball-bearing or roller mechanism. Require clearance – usually 1/2″ – between the drawer slides and the sides of the cabinet opening.

Center mount drawer slides are sold as single slides that, as the name suggests, mount under the center of the drawer. Available in classic wood version or with ball-bearing mechanism. Required clearance depends on thickness of slide.

Undermount drawer slides are ball-bearing slides that are sold in pairs. They mount to the sides of the cabinet and connect to locking devices attached to the underside of the drawer. Not visible when the drawer is open, making them a good choice if you want to highlight your cabinetry. Require less clearance between the drawer sides and the cabinet opening (usually 3/16″ to 1/4″ per side). Require specific clearance at top and bottom of cabinet opening; drawer sides typically can be no more than 5/8″ thick. Space from underside of drawer bottom to bottom of drawer sides must be 1/2″.

Drawer Slide Length
Slides most commonly come in sizes ranging from 10″ to 28″, though some shorter and longer slides are available for special applications.
For side-mount and center-mount slides, typically measure the distance from the front edge of the cabinet to the inside face of the cabinet back and then subtract 1″.
For under-mount slides, measure the drawer length. Slides must be the same length as drawer to work properly.