Drawer Size Calculator
Enter the cabinet opening width, height and depth, the slide type and the board thickness. The calculator gives the drawer box size, the slide length to buy, the bottom panel size and the cut list for sides, front and back.
- Drawer box size
- Slide length
- Cut list
Measure the opening inside the face frame or carcass, not the outside.
The drawer box must be narrower than the opening by the slide clearance. Side-mount ball bearing slides need 12.7 mm, half an inch, each side. A 500 mm wide opening takes a 474.6 mm wide box. The box depth is the longest standard slide that fits the cabinet.
Slide clearance chart
Per side. Search for a slide.
| Slide | Each side (mm) | Total (mm) | Box for 500 mm opening |
|---|---|---|---|
| Side-mount | 12.7 | 25.4 | 474.6 |
| Undermount | 8 | 16 | 484 |
| Centre-mount | 3 | 6 | 494 |
Check the maker's figures.
Opening and box
Side-mount slides, 150 mm high. Slide the opening width.
The front view shows the box in the opening with the slide gaps either side.
How to size a drawer
Opening to cut list. Step through it.
Measure the opening
W, H, D.
Build one test drawer before cutting a whole kitchen's worth.
Side-mount, undermount or centre
Slide types. Compare them.
Common.
Hidden.
Simple.
Undermount slides need a notched back and a recessed bottom, so follow the maker's drawing.
Before cutting
Drawer checks. Tick each item.
Tick each item as you go.
Square boxes run smoothly. Measure both diagonals before the glue sets.
What you get
Drawer sizing. Each tile explains one result.
W × H × D.
Length.
Panel.
Cut sizes.
Each side.
A false front is fitted after the box, so you can adjust the gaps round it.
Frequently Asked Questions
No question matches that search.
How much smaller should a drawer be than the opening?
For side-mount slides, twenty-five point four millimetres narrower in total, half an inch each side.
How do I choose a drawer slide length?
Use the longest standard slide that fits the cabinet depth with a little room at the back.
How much height clearance does a drawer need?
About twenty-five millimetres less than the opening, split top and bottom.
What size is the drawer bottom?
The inside size of the box plus the depth of the grooves on each side.
What clearance do undermount slides need?
Usually about eight millimetres a side, but follow the maker's guide.
Should the drawer box be the same depth as the slide?
Yes, for most slides the box matches the slide length.
What board is best for drawer boxes?
Twelve to fifteen millimetre birch plywood or solid wood.
Drawers that run sweetly
Size the box from the opening and the slides, cut carefully and square it up, and the drawers glide.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.