9 × 9 × 9 in box: dimensions, dim weight and strength
A 9 × 9 × 9 in box holds 729 in³ (0.42 ft³) inside. Made in C flute its outside is about 9.31 × 9.31 × 9.47 in, which dimensional weight bills USPS at actual weight (under its threshold) and FedEx at 6 lb.
Key numbers
| Inside (L × W × H) | 9 × 9 × 9 in |
|---|---|
| Inside volume | 729 in³ · 0.422 ft³ · 11.9 L |
| Inside, metric | 229 × 229 × 229 mm |
| Perimeter 2(L + W) | 36 in |
| Length + girth, C flute OD | 46.9 in |
Outside dimensions by flute
| Board | Caliper, in | Outside, in | Outside volume, ft³ |
|---|---|---|---|
| E flute | 0.063 | 9.13 × 9.13 × 9.19 | 0.443 |
| B flute | 0.125 | 9.25 × 9.25 × 9.38 | 0.464 |
| C flute | 0.156 | 9.31 × 9.31 × 9.47 | 0.475 |
| EB double wall | 0.188 | 9.38 × 9.38 × 9.56 | 0.486 |
| BC double wall | 0.281 | 9.56 × 9.56 × 9.84 | 0.521 |
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 | 10 × 10 × 10 | n/a | n/a |
| FedEx | 139 | 9 × 9 × 9 | 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 | 398 | 239 |
| 32 ECT C flute | 446 | 267 |
| 44 ECT C flute | 613 | 368 |
| 48 ECT C flute | 668 | 401 |
| 48 ECT BC double wall | 897 | 538 |
| 61 ECT BC double wall | 1,139 | 684 |
| 71 ECT BC double wall | 1,326 | 796 |
Simplified McKee: BCT ≈ 5.87 × ECT × √(caliper × 36). 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 | 20 | 5 | 100 | 52.8 | 78% |
| BC double wall | 20 | 5 | 100 | 54.7 | 86% |
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: 9.3125″ along the 48″ side.
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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