Rigid box sizing trips people up because a folding carton is essentially one thickness of board, while a rigid box is a built wall. If you hand over an exterior dimension and assume the product will fit, it will not. This page explains the geometry so your spec survives contact with production.
The wall build-up problem
A rigid wall is made of three things: the chipboard core, the wrap paper turned over the outside, and usually a liner or wrap on the inside. That stack sits on both sides of the box, so the exterior length is the interior length plus roughly two wall thicknesses. Repeat for width. Depth adds the base construction as well.
The exact figure depends on the chipboard caliper chosen for your job, which is selected against the size of the box and the weight it carries. Larger boxes and heavier contents need a thicker core, and a thicker core means a bigger jump between inside and outside. We confirm the caliper on the written quote rather than assuming one, because guessing here is how a box arrives that does not fit a shelf or a shipper.
Lid clearance on a two-piece box
| Element | What it is measured from | Why it matters |
|---|---|---|
| Base interior | The product plus its insert plus clearance | This is the only number you should send us |
| Base exterior | Base interior plus the wall build-up on each side | Determines shelf and shipper fit |
| Lid interior | Base exterior plus a seating clearance | Too tight and the lid binds, too loose and it rocks |
| Lid depth | How far the lid travels down the base | A full-depth lid looks different from a shallow one and uses more material |
The chain runs one way: product, then base interior, then base exterior, then lid. Break the chain at the wrong point and the box either crushes the product or swims around it.
Other rigid formats
- Shoulder neck. An inner collar sits proud of the base and the lid closes onto it. That collar is another wall thickness inside the cavity, so the usable interior shrinks unless it is accounted for.
- Drawer and sleeve. The drawer must slide, so there is clearance between drawer exterior and sleeve interior. Too little and it jams once the box is loaded.
- Magnetic flap. The magnet and its recess occupy depth in the wall, which affects the front panel thickness.
- Book style. The spine width is dictated by the base depth plus the hinge allowance, so a deep box needs a wider spine to open properly.
How to give us a spec that works
- Send the product dimensions and, if possible, a physical sample or a photo with a ruler.
- State the insert you want, or ask us to propose one.
- State any hard exterior limit, such as a shelf height, a shipper size or a mailing constraint.
- State the filled weight, because it drives the chipboard caliper.
From those four inputs we draw the dieline, confirm the build and issue a digital proof before anything is produced.
Cost, tooling and the rigid calendar
The minimum order is 100 boxes. Pricing starts from about $0.48 per unit at bulk volumes and is confirmed on your written quote. Die, plates, design support, free US shipping and the digital proof are included. Rigid boxes involve hand assembly, so lead times sit at the longer end: production runs from about 7 business days, plus 2 to 5 for delivery, and specialty imported rigid items can run up to about 12 weeks. Rush, standard and cost saver lanes are quoted per product.
Send us an interior target
Send your interior target and filled weight to /quote/. For construction options, see custom rigid boxes, and for the core material itself see rigid chipboard boxes.
