How to use the drawer size calculator
- Measure the usable cabinet opening and interior depth.
- Enter the clearances required by your chosen slides; do not assume the default fits every slide.
- Read the outside box dimensions. Front and back widths assume those parts fit between full-length sides.
The formula
Outside width = opening − 2 × side clearance; depth = available depth − allowance; height = opening − total vertical clearance
Worked example
A 500 × 200 mm opening with 550 mm depth, 12.7 mm clearance on each side, and 25 mm vertical and depth allowances gives a 474.6 × 525 × 175 mm box.
Before you measure and cut
The default side clearance represents a common style of side-mount slide, not a universal hardware requirement. Undermount systems can have very different details.
A separate drawer face, bottom groove, dovetails, rabbets, and slide notches are not included.
Frequently asked questions
Is the calculated depth a standard slide length?
Not necessarily. Choose a compatible available slide length and adjust the box depth to the manufacturer’s instructions.
Does it size the drawer bottom?
No. Bottom size depends on whether it is applied, captured in grooves, or fitted with expansion clearance.