Most businesses overspend on cartons in one of two ways: buying a stronger box than the product needs, or buying a cheap box that fails in transit and costs a replacement shipment. Getting the spec right comes down to three decisions — box style, flute type, and size. Here's how we walk our own customers through it.
Decision 1: RSC or die-cut?
A Regular Slotted Container (RSC) is the standard carton everyone pictures: four flaps top and bottom that meet in the middle. It's the cheapest style to manufacture because it wastes almost no board, and it ships flat.
Choose RSC when:
- You're shipping general goods in volume — cartons for storage, courier shipments, warehouse transfer
- Sealing with tape is acceptable
- Unit cost matters more than unboxing experience
A die-cut box is cut to a custom shape on a die — think mailer boxes with tuck flaps, pizza-style boxes, or cartons with built-in inserts. No tape needed, tighter product fit, and a much better presentation.
Choose die-cut when:
- The box is part of the product experience (e-commerce, retail, gifting)
- The product needs a snug fit or internal partitions
- You want tool-free assembly on a packing line
Decision 2: Which flute?
The flute is the wavy layer inside corrugated board. Flute choice controls cushioning, stacking strength, print quality, and thickness:
| Flute | Thickness | Best at | Typical use |
|---|---|---|---|
| A flute | ~5 mm | Cushioning and stacking strength | Shipping cartons that need extra protection |
| B flute | ~3 mm | Crush resistance, flat surface for print | Die-cut boxes, retail packaging, inner cartons |
| E flute | ~2 mm | Fine print surface, rigidity in thin board | Mailer boxes, product boxes, printed retail packs |
| BA flute (double wall) | ~8 mm | Heavy loads, tall stacking | Industrial parts, export cartons, heavier contents |
| BE flute (double wall) | ~5 mm | Double-wall strength with a smooth, printable face | Heavier printed shipping cartons |
Not sure which to pick? Tell us what's going in the box, roughly how heavy it is and how high the cartons will be stacked, and we'll recommend a flute. Double wall (BA or BE) is the usual step up when cartons are stacked high in a container or the contents are heavy or fragile.
Decision 3: Size — we quote external dimensions
We quote carton sizes as external length × width × height, measured on the outside of the box. Board has thickness, so the space inside is smaller than the outside size. If you order a carton at your product's exact size, the product won't fit.
- Measure your product (or product bundle) precisely.
- Add clearance: 3–5 mm per side for a snug fit, more if you're adding protective wrap.
- Add the board thickness on each side: about 3 mm for B flute, 5 mm for A flute, or 8 mm for BA double wall.
- Keep height as low as practical — shorter boxes stack stronger and cube out trucks better.
Not sure about the maths? Send us your product size and we'll work out the carton size for you, or try Pack Fit.
Quick checklist before you order
- Contents weight — determines flute and paper grade
- Stacking height in storage and transit — determines wall construction
- External dimensions — or just your product size, and we’ll work them out
- Quantity — unlocks better pricing tiers and custom printing
- Printing — even a one-colour logo and handling marks look professional and reduce mishandling
Send us these five details and we can quote a carton within 2 hours — usually with a sample before you commit to a full run.