A full overlap box, often written FOL, is a slotted container where the outer flaps are cut long enough to overlap each other completely across the top and the bottom. That gives you a double thickness of board on the two faces that take the most abuse in stacking and handling, which is why the style is chosen for heavy or shifting loads. Sizing one is the same discipline as any slotted box, with one extra consideration at the end.
Step by step
- Measure the load, not the old box. Take the product at its widest, tallest and deepest, in the orientation it will actually be packed. If several items go in, arrange them the way the packer will and measure the arrangement.
- Add clearance. Allow room for whatever separates the product from the wall: a liner, a corrugated pad, void fill or an insert. Tight is not the goal. A box that fights the packer slows the line and gets forced.
- Write it as internal length x width x depth. Length is the longer of the two open-face dimensions, width the shorter, depth the height from the inside floor to the score line. Use that order every time and nobody has to guess.
- Choose the board for the load. Weight, stack height and storage time decide single wall or double wall far more than the box dimensions do. Tell the supplier the loaded weight.
- Convert to external and check the fit. Add roughly two board calipers per axis, then check that external figure against your pallet footprint, your shelf and your carrier thresholds before the die is cut.
Flute caliper, and what it does to your outside dimension
These are nominal industry figures. Actual caliper varies between mills and with board grade, so treat them as planning numbers and confirm on the quote.
| Flute | Nominal caliper | Typical use |
|---|---|---|
| F | About 0.8 mm | Small retail cartons, printed surfaces |
| E | About 1.6 mm | Mailers, light retail shippers |
| B | About 3.2 mm | General shipping, good crush resistance |
| C | About 4.8 mm | The common general purpose shipping flute |
On a full overlap, the flap overlap adds a second thickness across the top and bottom faces. That is the point of the style, but it does mean the closed height of the box is not identical to a regular slotted container in the same internal size, and the difference shows up when you stack a pallet fourteen cases high. See what C flute is if you are deciding between grades.
When full overlap is the right style and when it is not
It earns its place when the load is heavy, when the contents can shift, when the box is handled repeatedly, or when a single wall board with double-thick faces is cheaper than stepping the whole box up to double wall. It is the wrong choice when you need the lowest possible material cost per box and the load is light and stable, because you are paying for board area you do not need. If you are unsure whether you even want this style, full overlap box dimensions sets out the shape in more detail.
Custom internal sizes cost no more to tool
The cutting die and the printing plates are included on iBox orders. That matters here more than on most styles, because the entire benefit of a full overlap comes from fitting the load properly. There is no tooling reason to round your internal dimension to a near-standard figure, and a box that fits reduces void fill, dimensional weight and product movement in one move.
Ordering
Minimum order is 100 boxes. Unit pricing starts from about $0.48 per unit at bulk volumes and is confirmed on your written quote, with design support, US shipping and a digital proof included. Three production lanes are available: rush (expedited production with air freight), standard (air) and cost saver (sea), from about 7 business days, plus 2 to 5 for delivery. Boxes are made at West Chicago and at Guangzhou.
If you have the three internal numbers and the loaded weight, that is a complete brief. Send it through the quote form and we will come back with a board specification and an external dimension to check against your pallet.
