How to Build a Drawer Box

The sizing formulas

Measure the internal opening of the carcase:

Box width  = internal width − slide clearance (side-mount ≈ 26 mm, under-mount ≈ 6 mm)
Side length = internal depth − front thickness
Side height = front height − 16 mm
Back width  = box width − 2 × side thickness
Bottom      = (box width − 2 × side thickness − 2) × (side length − 2)

Joinery options

Build steps

1. Cut sides, front, back and bottom to size.
2. Cut the joinery and the bottom groove (4–6 mm deep, ~6 mm from the bottom edge).
3. Dry-fit the box and check it slides in the carcase.
4. Glue the box, insert the bottom (plywood or hardboard), clamp square.
5. Mount the slides per the manufacturer datasheet.

Practical tips

• Always follow the slide datasheet — clearances vary by brand.
• Leave 2–3 mm vertical play so the drawer runs smoothly.
• Soft-close under-mount slides need exact box width.

Size every panel with the drawer calculator, then cut with the wood cutting calculator.