What box for 20 × 30 in prints? Inside sizes and dim weight

20 × 30 in prints measure 20 × 30 in. With 1 in of cushioning on every side, a 1 in stack needs a box at least 32 × 22 × 3 in inside; a shallow die-cut mailer or a telescope box suits flat goods better than a deep slotted carton.

Inside sizes by stack thickness and cushioning

Stack, in	Cushion per side	Inside box, in	Suggested style	Smallest library size that fits	USPS DW	FedEx DW
0.5	0.5	31 × 21 × 1.5	0427	32 × 24 × 18	n/a	10 lb
0.5	1	32 × 22 × 2.5	0427	32 × 24 × 18	17 lb	16 lb
0.5	2	34 × 24 × 4.5	0427	36 × 24 × 24	32 lb	30 lb
1	0.5	31 × 21 × 2	0427	32 × 24 × 18	16 lb	10 lb
1	1	32 × 22 × 3	0427	32 × 24 × 18	22 lb	16 lb
1	2	34 × 24 × 5	0427	36 × 24 × 24	38 lb	30 lb
2	0.5	31 × 21 × 3	0427	32 × 24 × 18	21 lb	15 lb
2	1	32 × 22 × 4	0427	32 × 24 × 18	28 lb	21 lb
2	2	34 × 24 × 6	0427	36 × 24 × 24	45 lb	36 lb
4	0.5	31 × 21 × 5	0427	32 × 24 × 18	31 lb	24 lb
4	1	32 × 22 × 6	0427	32 × 24 × 18	39 lb	31 lb
4	2	34 × 24 × 8	0301	36 × 24 × 24	57 lb	47 lb

Inside = item + 2 × cushion on each axis. Dimensional weight uses C flute outside dimensions (ID + 2 calipers on L and W, + 3 on depth); n/a means USPS bills actual weight below 1,728 in³. Divisors checked 2026-10-27. The suggested style is a rule of thumb: 0427 for depths to 6 in, 0301 beyond.

Packing notes

Keep flat goods flat: a box whose depth is far more than the stack invites shifting, so fill or reduce the depth.
Corners take the knocks; corner protectors or a rigid pad on each face protect edges better than loose fill.
Large sheets (30 in long side) are often rolled into tubes instead; a flat box this size bills heavily by dimensional weight.

Open this item in the Spec Builder to set your own thickness, weight and carriers.

Other formats

Sources

Nominal print size: the name is the trimmed size in inches
USPS Domestic Mail Manual 223 (Priority Mail prices and eligibility), section 1.4
FedEx: What is dimensional weight?

Last reviewed 2026-10-27. See all sources and how Packgent computes.