WoodTools

Drawer Calculator

Drawer boxes are all about clearances. Enter the cabinet opening, pick a slide profile, and get every panel of the drawer box cut to size.

An exploded drawer box with front, sides, back, bottom and a side-mount slide. front width FRONT SIDE BACK BOTTOM drawer width side length SLIDE
Advertisement

Workshop AI assistant

Describe the piece you want to build and get a complete plan: dimensions, cut list, materials, cost, steps, tools and time.

Workshop assistant

Describe the piece you want to build and get a complete plan: dimensions, cut list, materials, cost, steps, tools and time.

AI-generated results are indicative. Verify dimensions, loads and local codes before building.

Advertisement

How it works

  1. 1

    Measure the internal opening width, depth and height of the carcase opening.

  2. 2

    Choose a slide profile (side-mount, under-mount…).

  3. 3

    Enter the material thickness of the drawer sides, front and bottom.

  4. 4

    Calculate: you get side, front, back and bottom panel sizes plus clearances.

Formula

Side length = internal depth − front panel thickness (for drawers with a front mounted on the box) or internal depth for a front covering the opening. Side height = front height − material clearance. Drawer width = internal width − slide clearance (typically 2× the slide thickness). Bottom = (drawer width − 2×side thickness) × side length.

Practical tips

  • Always read the slide manufacturer datasheet — clearances differ by brand.

  • Cut the bottom in 4–6 mm plywood or hardboard, stapled or sliding in a groove.

  • Add 2–3 mm vertical play so the drawer runs even if the carcase settles.

  • For soft-close slides, respect the recommended box width precisely.

Common mistakes

  • Using the external width instead of the internal opening width.

  • Forgetting the slide thickness on both sides.

  • Making the front exactly the opening size with no reveal or overlap.

  • Ignoring the manufacturer clearance for soft-close under-mount slides.

Advertisement

Disclaimer

These results are indicative only. Always verify against local building codes, standards and professional advice before building.

Related tools

Related guides

Related projects

Frequently asked questions

Why is the drawer narrower than the opening?
Side-mount slides sit on both inner walls and take about 13–15 mm each side. Under-mount slides are fixed under the drawer and need less side clearance.
What thickness should drawer parts be?
Commonly 12–16 mm for sides, 16–19 mm for the front, and 4–6 mm for the bottom.
Can I use this for kitchen drawers?
Yes — kitchen carcases are the most common use. Pair it with the furniture plan generator for the carcase and doors.
All tools