FEFCO 0203: Full overlap slotted container (FOL)

A full overlap container has outer flaps as long as the box is wide, so each closed end has the outer flaps lying fully on top of each other. That puts extra layers of board across the top and bottom, which helps with rough handling and with stacking the box on its side.

Dieline

Drawn by Packgent from the style's flap rule. Solid lines are cuts, dashed lines are scores.

Construction

The usual four panels and manufacturer's joint.
Every flap is the full inside width long. When closed, the outer flaps lie across the full width, stacked on each other.
The inner flaps are the same length, so on a box longer than it is wide they also overlap.

Flap and panel rule
Part	Size
All flaps	W
Layers at each end	two full layers of outer flaps plus the inner flaps

Closure. Glue, staple or tape. The full overlap gives a wide area for glue or stitches.

Blank size

Blank width is H + 2W, against H + W for an RSC: the extra board is the price of the extra layers.

Worked example at 12 × 10 × 8 in inside
Board	Nominal blank, in	With allowances, in	Area, ft²
B flute	45.25 × 28	45.75 × 28.25	8.98
C flute	45.25 × 28	45.88 × 28.31	9.02
BC double wall	45.25 × 28	46.38 × 28.56	9.2

Allowances add one caliper per vertical score and per flap score. Your box maker sets the real scores. Work out other sizes with the box blank calculator.

Estimated compression strength

Simplified McKee estimate for the empty box at 12 × 10 × 8 in. The flap style barely changes McKee's answer, because it depends on the walls; extra flap layers help with drops and side stacking more than with top-to-bottom load.

ECT, lb/in	B flute BCT, lbf	C flute BCT, lbf
32 ECT	441	493
44 ECT	606	677
48 ECT	661	739

Estimate only. Confirm with an ASTM D642 test before relying on it. Run the McKee calculator.

When to use it

Good for

Heavy or dense contents
Boxes shipped or stored on their side
Drop-prone parcel routes

Watch for

The blank is much wider (H + 2W), so board use goes up
Very wide boxes give very long flaps, which can be awkward to fold by hand

Open the Spec Builder to check style, grade and dimensional weight for your product.

Related styles

Sources

Fibre Box Association, "Box Styles Basics" (2014), hosted by IoPP
FEFCO: The FEFCO Code (International Fibreboard Case Code), 12th edition
McKee, R.C., Gander, J.W. & Wachuta, J.R. (1963). "Compression strength formula for corrugated boxes." Paperboard Packaging 48(8): 149–159

Last reviewed 2026-10-27. See all sources and how Packgent computes.