A half slotted container is a regular slotted box with the flaps cut away from one end. That open end is the point: it lets the box work as a tray that a cap, a lid or a second tray closes over. Sizing one is the same discipline as any corrugated box, with two extra things to watch, the flap geometry and the cap fit.
Six steps to an internal size
- Measure the product at its widest on all three axes. Not the nominal size, the measured size, including anything that protrudes.
- Add clearance for whatever holds the product. A die cut insert adds its wall caliper on each side. Void fill adds the thickness you intend to use. Nothing at all still needs a working clearance so the product loads without scraping.
- Order the numbers correctly. Length is the longer of the two horizontal spans at the open face, width is the shorter, depth is the vertical distance from the inside bottom to the top edge.
- Check the flap geometry. On the closed end, the flaps are cut at half the width so they meet in the centre. An unusual length-to-width ratio can leave you with a gap or an overlap, both of which matter if that end carries load.
- Pick board from load and stack height. Send the loaded weight of one box and the maximum stack height. Board grade is a response to those numbers, not to the product category.
- State internal or external. This is the single most common source of a box that arrives a quarter inch short.
Internal to external by flute
Every axis gains roughly two board thicknesses when you convert internal to external, because there is board on both sides. These are published flute calipers, useful for estimating before a quote confirms the exact board.
| Flute | Approximate caliper | Approximate gain per axis |
|---|---|---|
| E | About 1/16 in | About 1/8 in |
| B | About 1/8 in | About 1/4 in |
| C | About 3/16 in | About 3/8 in |
| BC double wall | About 5/16 in | About 5/8 in |
More detail on flute selection is on our flute guide.
Sizing the cap that closes it
A half slotted box is only half the package. The cap, whether it is a second HSC inverted over the first or a separate telescoping lid, has to be sized on the external dimension of the tray, not on the internal. Decide the overlap you want: a shallow cap covers a few inches and relies on the tray for strength, a full telescoping cap covers most of the tray depth and adds meaningful stacking strength because two thicknesses of board carry the sidewall.
Why a custom internal size costs nothing extra to tool
The die and the plates are included on every order, so a box cut to your exact product costs no more to tool than one built to a near-standard size. That changes the economics of sizing: there is no reason to squeeze a product into a nearby stock dimension and pay for the void fill, the extra board and the dimensional weight that come with it. Size the box to the product.
Ordering and turnaround
Minimum order is 100 boxes, from about $0.48 per unit at bulk volumes, confirmed on your written quote. Design support, US shipping and a digital proof before printing are included. We produce in West Chicago in the US and in Guangzhou in China. Turnaround is quoted per product in three lanes: rush (expedited production plus air freight), standard (air) and cost saver (sea), from about 7 business days in production plus 2 to 5 days for delivery. If you would rather answer a few questions than work through a method, see what size half slotted box do I need, or go straight to corrugated boxes.
Send your three product measurements, the loaded weight and the stack height. Request a quote and we will confirm the internal size, the board and the cap together.
