Custom Shipping Boxes

Inside a regular slotted carton

Flat sheets of corrugated, scored and slotted, then joined along one seam so the tube folds up into a box.

The common style is the regular slotted carton. All four flaps are cut from the same sheet, and the outer flaps meet in the middle of the top and bottom. The seam is glued, taped or stitched at the factory, and the box arrives flat.

Corrugated gets its strength from a fluted layer between two flat liners. The arches resist crushing from above and the liners resist tearing and puncture. The liners and the flute are chosen together, because the box is only as strong as the weaker of the two jobs.

• Fluted medium sandwiched between liners
• One factory seam, everything else folds
• Ships flat, closed with tape or a crash-lock base

Single wall, double wall, and which flute

Single wall is enough for most parcels. Double wall earns its place when weight, stacking or rough routes are the real risk.

Single wall has one fluted layer. B-flute is about 3mm thick and cushions well, C-flute is a little thicker and stacks better, and E-flute is thin and suits lighter goods. Double wall joins two fluted layers, often B and C, for far more crush resistance and a much stiffer panel.

The cost of double wall is bulk and weight. Each flat box takes more storage space, folds less crisply and adds to the billed weight. Choose it for heavy items, long routes with several handovers, and boxes that will sit at the bottom of a stack. Tell us the heaviest load and how high the boxes stack, and we recommend the wall.

• Single wall: lighter, easier to store, fine for most DTC parcels
• Double wall: heavy or fragile goods, pallets, long routes
• Edge crush rating matters once boxes stack high

Measure the product, then the gap

Record internal length, width and height in that order, and measure the product with its inner packing, not bare.

A shipping box is specified by the space inside it. Add room for any bag, wrap or insert, then a few millimetres of clearance on each side. A box that is too tight bulges at the seams and splits at the corners. A box that is too loose lets the contents move, and movement causes most damage.

Size also drives the freight bill. Carriers convert a parcel's volume into a billed weight and charge whichever figure is higher, so a box a few centimetres too deep costs more on every shipment. Trim the height first, because it is the easiest dimension to waste, and tell us the parcel size you aim for so we keep the box inside it.

• Internal dimensions, length then width then height
• Measure the product with its inner packing
• Check the carrier's size bands before finalising

Shipping box or padded bag?

A padded bag is lighter and cheaper to post. A corrugated box protects against crushing, which a bag cannot do.

Bags and poly mailers suit soft goods that cannot be crushed, such as clothing and textiles. They add almost nothing to a parcel's size or weight, and they lie flat in a delivery van.

Once a product is rigid, brittle or valuable, a box is the safer choice. The walls carry the load of other parcels stacked on top, and the box gives you something to build a fitted insert into. A mailer box sits between the two, but a plain shipper is still the better fit for heavy, mixed or bulk orders.

Printing on corrugated

One or two colours, printed straight onto the board, is the usual approach and it holds up well in transit.

Corrugated is printed with water-based inks, normally by flexography. The surface is slightly textured and the fluting can show faintly through the liner, so large logos, bold type and simple shapes reproduce well. Fine screens and photographs do not.

Kraft liner is brown and ink sits on top of it, which darkens every colour. Light and pastel tones barely register. A white top liner gives truer colour but reads as less natural. A plain or one-colour box is a sound choice for wholesale cases and for boxes that travel inside a larger carton.

Shipping box or mailer box?

A shipping box is the pick for transit, wholesale and bulk. A mailer box is the pick when the opening is part of the product.

A shipper is built to survive transit, not to be looked at. It is the wrong shape for a shelf and its print is limited, and a customer opening one expects the goods, not an experience. Where the unboxing matters, a printed mailer box is the better fit.

It is also oversized for very small, light items. A carton sized for a single lipstick adds weight and tape for no benefit. Long, thin goods suit a telescope style, and very heavy loads a double-wall build of the same box.