Drawer Slide Calculator — Drawer & Slide Dimensions

Ball bearing slides typically require 12.7mm (1/2 inch) clearance on each side. So the drawer box width should be 25.4mm narrower than the cabinet opening. Always check the manufacturer specifications as some slides may differ slightly.

Ball bearing slides use steel ball bearings for smooth, full-extension movement and can support heavier loads (typically 35-45 kg). Euro or roller slides use nylon rollers, are cheaper, and usually offer 3/4 extension only. Ball bearing slides are preferred for kitchen drawers and heavy-duty use.

The slide must be shorter than the cabinet depth, allowing roughly 25mm rear clearance behind the drawer. Slides come in standard lengths at 50mm increments (250mm to 600mm), so this calculator rounds down to the largest standard length that fits, and sizes the drawer box depth to match that slide so the box never overhangs the runner.

Undermount slides (like Blum Tandem) mount underneath the drawer and do not use a side clearance gap. Instead, Blum specifies the drawer INSIDE width — the width of the bottom and back panels between the sides. For sides up to 16mm (5/8 inch, model 563H) the inside width is the cabinet opening minus 42mm; for sides over 16mm up to 19mm (3/4 inch, model 563F) it is the opening minus 49mm. The outer box width is that inside width plus twice your side thickness. Blum tolerance allows the inside width to be up to 1.5mm narrower but never wider, as a wider box binds the runners. Always refer to the manufacturer fitting guide for exact dimensions.