What the form asks for
Three size fields describe the empty space inside the finished box: inner width, inner depth and inner height, in millimetres or inches. A fourth field holds the material thickness, because the walls are added around the space you typed. The outside of the box is a result, not a field: the summary shows it and the part list gives the size of every panel.
From the inside to the outside
- Width and depth. outer = inner + 2 × thickness: one wall on each side.
- Height of a closed box. outer = inner + 2 × thickness: the bottom panel and the top panel.
- Height of an open tray. outer = inner + 1 × thickness: only the bottom panel.
Kerf does not change these sizes. It only moves the drawn outline outwards by half the kerf, so that the cut part comes out at the size above. The kerf page explains that step.
Measuring the object
Measure the object at its widest, deepest and tallest point. Then add the clearance you want yourself: the generator adds none, and the inner size you type is the inner size it draws. A millimetre or two in each direction is a reasonable first try for a loose fit.
Worked example: an object of 118 × 78 × 44 mm
With 2 mm of clearance in each direction the inner size is 120 × 80 × 46 mm. The sheet is 3 mm thick.
| Direction | Inner | Sum | Outer |
|---|---|---|---|
| Width | 120 mm | 120 + 2 × 3 | 126 mm |
| Depth | 80 mm | 80 + 2 × 3 | 86 mm |
| Height, closed box | 46 mm | 46 + 2 × 3 | 52 mm |
| Height, open tray | 46 mm | 46 + 1 × 3 | 49 mm |
These figures come from the sums in the table and from nothing else: this box was not generated for this page and was not cut. Check that the outer size fits the shelf or drawer the box goes into before you cut.
Limits the form enforces
- Every inner side must be greater than 0, and the largest one 3000 mm or less.
- The material thickness must be less than half the smallest inner side. In 3 mm sheet the smallest inner side has to be above 6 mm.
When a value breaks a rule the form shows a message that names it.
Read this before you buy or cut
- Dimensions. You enter the inner width, depth and height. The outer size is the inner size plus two material thicknesses (an open tray has no lid panel, so its outer height is the inner height plus one thickness).
- Not test-cut. The geometry is computed and checked by a script (92 fixture assertions) but was never test-cut, so cut a test piece first and adjust kerf and material thickness.
- Made by AI agents. This tool and its code were generated by AI agents and no human maker has validated it.
- Price: $9 USD one-time.
- What the key unlocks: one licence key unlocks SVG and DXF download for any dimensions, in this browser tool.
- Refunds: Refund requests go through Gumroad, under Gumroad's refund policy.
- Free without a key. The form, the preview, the part list and the sheet size.