12 × 8 × 8 in box: dimensions, dim weight and strength
A 12 × 8 × 8 in box holds 768 in³ (0.44 ft³) inside. Made in C flute its outside is about 12.31 × 8.31 × 8.47 in, which dimensional weight bills USPS at actual weight (under its threshold) and FedEx at 6 lb.
Key numbers
| Inside (L × W × H) | 12 × 8 × 8 in |
|---|---|
| Inside volume | 768 in³ · 0.444 ft³ · 12.6 L |
| Inside, metric | 305 × 203 × 203 mm |
| Perimeter 2(L + W) | 40 in |
| Length + girth, C flute OD | 45.9 in |
Outside dimensions by flute
| Board | Caliper, in | Outside, in | Outside volume, ft³ |
|---|---|---|---|
| E flute | 0.063 | 12.13 × 8.13 × 8.19 | 0.467 |
| B flute | 0.125 | 12.25 × 8.25 × 8.38 | 0.49 |
| C flute | 0.156 | 12.31 × 8.31 × 8.47 | 0.502 |
| EB double wall | 0.188 | 12.38 × 8.38 × 8.56 | 0.514 |
| BC double wall | 0.281 | 12.56 × 8.56 × 8.84 | 0.551 |
OD ≈ ID + 2 calipers on length and width, + 3 on depth. An estimate: your box maker sets the scores. Convert other sizes.
Dimensional weight
| Carrier | Divisor | Measured, in (C) | DW, C flute | DW, BC double wall |
|---|---|---|---|---|
| USPS | 139 | 13 × 9 × 9 | n/a | n/a |
| FedEx | 139 | 12 × 8 × 8 | 6 lb | 8 lb |
DW = ⌈L × W × H ÷ divisor⌉ on outside dimensions, after each carrier's own rounding. USPS applies it only above 1,728 in³ (n/a means it bills actual weight). The carrier bills the greater of actual and dimensional weight. Divisors checked on carrier pages 2026-10-27; try your own weight.
Estimated compression strength
| Board | BCT, lbf | After 30 days storage |
|---|---|---|
| 32 ECT B flute | 420 | 252 |
| 32 ECT C flute | 470 | 282 |
| 44 ECT C flute | 646 | 387 |
| 48 ECT C flute | 704 | 423 |
| 48 ECT BC double wall | 945 | 567 |
| 61 ECT BC double wall | 1,201 | 721 |
| 71 ECT BC double wall | 1,398 | 839 |
Simplified McKee: BCT ≈ 5.87 × ECT × √(caliper × 40). The 30-day column applies Packgent's default 40% storage loss, an assumption. Estimates only; test with ASTM D642.
Pallet pattern on 48 × 40
| Board | Per layer | Layers | Boxes per pallet | Load height, in | Cube used |
|---|---|---|---|---|---|
| C flute | 16 | 6 | 96 | 56.3 | 80% |
| BC double wall | 16 | 6 | 96 | 58.6 | 87% |
Column stacked, no overhang, on a 48 × 40 in deck 5.5 in tall, loaded to 60 in overall. Those three are assumptions you can change in the pallet calculator. Pattern: two-zone (1 rows turned).
Blank size in C flute
With one caliper allowance per score. Multiply board area by your board's combined weight (lb/MSF ÷ 1,000) for box weight, or use the box weight calculator.
Sources
- USPS Domestic Mail Manual 223 (Priority Mail prices and eligibility), section 1.4
- FedEx: What is dimensional weight?
- Flute calipers: Foster (1997), Wiley Encyclopedia of Packaging Technology
- McKee, Gander & Wachuta (1963), Paperboard Packaging 48(8)
Last reviewed . See all sources and how Packgent computes.
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