How to measure a game box interior
Your insert has to fit the smallest inside dimension of the box, below whatever sits on top of it.
Width and length
- Take out everything, including the stock insert. Measure the inside of the bottom of the box, wall to wall, along both edges and through the middle. Use the smallest of the readings.
- Check near the floor as well as at the rim. Corners are often filled with glue or rounded, and some boxes taper slightly.
- If the game came with a cardboard insert, measure that too. It was made to fit, which makes it a useful cross-check (Fractal Thought).
- A plastic ruler's zero is often worn or set back from the end. One builder recommends measuring from the 1 cm mark and subtracting 1 cm (same source).
Usable depth
Measure the inside depth from the floor to the rim. Then subtract everything that will sit on top of the insert: the folded board, rulebook, player aids, and any punchboards you keep. Guides commonly recommend leaving 1–2 mm under the lid (Desktop CNC Forge). Enter the full inside depth in the designer and put the rest in Clearance under the lid, so the arithmetic stays visible.
Clearance at the walls
Experienced builders don't agree. Some fit the base snugly and let it settle in (Fractal Thought). Others leave "a gift card's width" so trays aren't jammed in (The Cardboard Shelf). Our default of 1 mm per side is a starting point, not a rule. Use more for trays you want to lift out (see removable trays).
Test before you commit
Cut the base of your first tray and push it into the box before you cut anything else. If it binds, trim the base and reduce the box size in the designer by the same amount. Every other part then updates to match.