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A regular slotted container is one folded sheet. Its flat blank unrolls the four side panels along the length — 2 × (length + width) plus a manufacturer’s joint — and its height equals the box depth plus the two flaps that meet at the centre, so the blank width is width + depth. You specify interior dimensions so the product fits; the plant adds a board-thickness allowance so the finished inside isn’t squeezed.
- Interior 12 × 10 × 8 in.
- Blank length = 2 × (12 + 10) + 1.5 = 45.5 in.
- Blank width = 10 + 8 = 18 in.
- Cut plan: four side panels + slotted flaps, glued/taped at the 1.5 in joint.
Reference tables
RSC blank from interior L × W × D
| Interior (in) | Blank L × W (in) |
|---|---|
| 12 × 10 × 8 | 45.5 × 18 |
| 16 × 12 × 12 | 57.5 × 24 |
| 18 × 18 × 18 | 73.5 × 36 |
| 24 × 16 × 12 | 81.5 × 28 |
Board-thickness allowance to add to interior
| Board | Add per dimension |
|---|---|
| Single-wall | ≈ 3/16 in |
| Double-wall | ≈ 5/16 in |
| Triple-wall | ≈ 1/2 in |
A number the tables do not give: a 12×10×8 in interior RSC unfolds to a 45.5 × 18 in blank once you add a 1.5 in joint.
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FAQ
What is an RSC?
A Regular Slotted Container — the most common box, one blank with flaps of equal length that meet at the centre. Most cartons you ship are RSCs.
Interior or exterior dimensions?
Always order by interior for product fit. The plant converts to a cut size by adding a board-thickness allowance so the inside clears the product.
What is the manufacturer’s joint?
The overlap where the box is glued, taped or stitched — usually about 1.5 in added to the blank length. It does not add interior space.
How do flaps affect the size?
On an RSC every flap is half the width, so the outer (major) flaps meet at the centre regardless of the box length. The inner (minor) flaps only fully meet when length equals width — that is normal and the box still closes. For a fully covered double top on long or heavy boxes, a Full-Overlap (FOL) or 5-panel folder covers the whole opening.
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