What an FOL is
A full-overlap slotted container is built like a regular slotted container, but the outer flaps are cut to the full box width instead of half — so when they fold in, they overlap all the way across. That gives every FOL a double layer of board on the top and bottom, which is exactly where a stacked or dropped box takes the most abuse. It ships and stores flat and squares up the same way an RSC does.
When to use an FOL
- Heavy or dense contents. The doubled deck resists bulging and top-load crush better than an RSC.
- Rough handling. The overlap protects the box's most vulnerable edges from impact and abrasion.
- Long, narrow boxes. Where an RSC's half-width flaps would leave a gap, the FOL's full-width flaps always close.
How it's specified
Like any corrugated box, an FOL is called out as length × width × depth (inside dimensions). The flat width is identical to an RSC, but the flat height grows because each flap is now full width rather than half:
| Blank dimension | Formula | Why |
|---|---|---|
| Flat width | 2·L + 2·W + joint | The four walls plus the glue joint |
| Flat height | D + 2·W | The wall depth plus a full-width flap top and bottom |
The extra board is the trade-off — an FOL weighs and costs more than the equivalent RSC. Weigh the strength gain against it with the box compression calculator.
Strengths and trade-offs
The FOL buys strength and protection with material. For heavy, fragile, or roughly handled goods it's often cheaper than a plain RSC plus separate reinforcement. For light, well-cubed product it's over-built — the RSC will ship the same thing for less. It's a targeted upgrade, not a default.
Questions
What is a full-overlap container?
A full-overlap container (FOL) is a corrugated box like an RSC, but the outer top and bottom flaps run the full width of the box and overlap completely, giving a double layer of board on the top and bottom for extra strength.
What is the difference between FOL and RSC?
On an RSC the outer flaps are half the box width and just meet in the middle. On an FOL they are full width and overlap all the way, so the FOL has a doubled top and bottom that resists crush and impact better, using more board.
When should I use an FOL box?
Choose an FOL for heavy or dense contents, rough handling, or long narrow boxes where RSC flaps would not meet. For light, well-cubed product an RSC is usually more economical.
Does an FOL cost more than an RSC?
Yes, because the full-width overlapping flaps use more board. The extra cost buys stacking strength and edge protection, so it pays off for heavy, fragile, or roughly handled goods.
Spec a tougher box, priced.
PackOS turns dimensions into a dieline, a 3D proof, and a quote — with board, pallet, and freight worked out as you go.