Drawer box calculator
A drawer box has to be exactly as narrow as its runners need. Too wide and it binds; too narrow and it falls out. Start from the opening, the runner clearance and the runner length.
How the box is sized
Width
Opening width − 2 × runner clearance. Side-mount ball-bearing runners commonly need 12.5 mm per side.
Length
The runner length; the box sides run full length.
Parts
Two sides, a front and back between them, and a base screwed under the box.
A worked example
Three drawers give six sides, six fronts and backs and three bases — count them on your sheet with one click.
Choosing the runner and board
Runner length
Runners are sold in fixed lengths. Take the cabinet’s inside depth, allow for the back and the front, and choose the longest runner that fits.
Sides and ends
15 mm or 18 mm board, ideally the same on every box so the parts list stays short.
Base
Often a thinner board; open the list in the optimiser and move the bases to their own material.
Check your runners
Runner makers decideUndermount and soft-close runners use different rules — clearance at the bottom and a set difference between opening and box. Use the figures in the runner’s own instructions; enter them as the clearance.
Drawer fronts are separate: size them like doors, from the opening and the gaps you work to — see the cabinet door calculator.
Questions
What clearance do drawer runners need?
Side-mount ball-bearing runners are commonly 12.5 mm per side. Always check the runner’s data sheet.
What board is used for drawer boxes?
15 mm or 18 mm board is common for sides; the base is often thinner.
Does it size the front?
No, the decorative front is sized like a door. This tool sizes the box.
Can I drill the runner holes?
Yes. Open the parts in the optimiser and add holes or a 32 mm row to the sides in the machining editor, then export BPP, MPR or DXF.
Plan your cut list now
Free, in the browser, with no account. Layouts, edging totals and machine files from one list.