Shipping Box Sizes Chart: Dim Weight & Boxes per Pallet

Quick answers
Billed on size from (UPS / FedEx)	any box whose L × W × H ÷ 139 beats its weight: a 12 × 12 × 12 bills at least 13 lb
USPS dim weight	only above 1 ft³ (1,728 in³); smaller boxes pay the actual weight
USPS largest parcel	70 lb, 108 in length + girth (130 in for Ground Advantage Commercial)
USPS Flat Rate boxes	one price per box up to 70 lb, no dim weight: sizes below

Rectangular box sizes

Box (in)	ft³	UPS, FedEx	USPS	Per pallet
12 × 9 × 6 Uline S-18339	0.38	5 lb	actual	170 (17×10)
12 × 12 × 7 Uline S-4613	0.58	8 lb	actual	108 (12×9)
18 × 12 × 6 Uline S-4187	0.75	10 lb	actual	80 (8×10)
12 × 12 × 10 Uline S-4126	0.83	11 lb	actual	72 (12×6)
16 × 12 × 8 Uline S-4235	0.89	12 lb	actual	80 (10×8)
14 × 12 × 12 Uline S-4407	1.17	15 lb	15 lb	55 (11×5)
17 × 12 × 12 Uline S-13309	1.42	18 lb	18 lb	40 (8×5)
18 × 12 × 12 Uline S-16380	1.50	19 lb	19 lb	40 (8×5)
16 × 12 × 18 Uline S-22657	2.00	25 lb	25 lb	30 (10×3)
18 × 16 × 12 Uline S-4728	2.00	25 lb	25 lb	30 (6×5)
20 × 18 × 18 Uline S-14286	3.75	47 lb	47 lb	12 (4×3)
24 × 16 × 18 Uline S-19054	4.00	50 lb	50 lb	15 (5×3)
24 × 18 × 16 Uline S-4698	4.00	50 lb	50 lb	16 (4×4)

Stock sizes from Uline’s 200 lb test corrugated box catalog, smallest to largest by volume. We found no ranking of the most common sizes from Uline, UPS or USPS. Columns: dimensional weight at each carrier; boxes per 48 × 40 pallet (per layer × layers).

Cube box sizes

Cube (in)	ft³	UPS, FedEx	USPS	Per pallet
6 × 6 × 6	0.13	2 lb	actual	480 (48×10)
8 × 8 × 8	0.30	4 lb	actual	240 (30×8)
10 × 10 × 10	0.58	8 lb	actual	96 (16×6)
12 × 12 × 12	1.00	13 lb	actual	60 (12×5)
14 × 14 × 14	1.59	20 lb	20 lb	24 (6×4)
16 × 16 × 16	2.37	30 lb	30 lb	24 (6×4)
18 × 18 × 18	3.38	42 lb	42 lb	12 (4×3)
20 × 20 × 20	4.63	58 lb	58 lb	12 (4×3)
24 × 24 × 24	8.00	100 lb	70 lb*	4 (2×2)

Uline sells cube boxes in every inch from 3 to 26 in, then 28, 30, 32 and 36 in. * A 24-inch cube has a USPS dim weight of 100 lb, but USPS charges the 70 lb price for anything above 70 lb.

How to read the tables

Dim weight is length × width × height ÷ 139, rounded up to the pound: the weight a parcel carrier bills when the box is lighter than that. UPS and FedEx round each side to the nearest inch; USPS rounds sides up and only applies dimensional weight above one cubic foot (1,728 in³): “actual” means USPS bills the actual weight.
Per pallet is how many boxes fit on a 48 × 40 in pallet stacked to 72 in including a 6.5 in pallet, all boxes standing the same way up, in simple block patterns (boxes per layer × layers). Another pattern can sometimes fit a few more. Weight is not limited here: heavy boxes may hit the pallet’s weight limit first.
Sizes are in inches, length × width × height, as the catalog lists them. Carriers measure the outside of the packed box, which is a little larger than a catalog’s inside size.

USPS Flat Rate box sizes

Box	Outside (in)	Inside (in)
Small Flat Rate Box	8-11/16 × 5-7/16 × 1-3/4	8-5/8 × 5-3/8 × 1-5/8
Medium Flat Rate Box, top loading	11-1/4 × 8-3/4 × 6	11 × 8-1/2 × 5-1/2
Medium Flat Rate Box, side loading	14-1/8 × 12 × 3-1/2	13-5/8 × 11-7/8 × 3-3/8
Large Flat Rate Box	12-1/4 × 12 × 6	12 × 11-3/4 × 5-1/2

From the USPS Domestic Mail Manual Flat Rate reference. Flat Rate boxes are charged a flat rate regardless of the actual weight, up to 70 lb (DMM 223, 1.5), so dimensional weight does not change their price.

USPS size and weight limits

Any USPS parcel can weigh up to 70 lb and measure up to 108 in in length and girth combined; USPS Ground Advantage Commercial allows up to 130 in. Length is the longest side; girth is the distance around the thickest part (2 × width + 2 × height for a box). Source: DMM 201, 7.3.

Choosing a box size

Use the smallest box the item fits in with its padding. Every inch counts: a 12 × 12 × 12 box has a dim weight of 13 lb, so a lighter item in it pays for 13 lb.
Measure the packed box outside, at the widest point of each side, bulges included.
Check the billable weight in the dimensional weight calculator, which shows UPS, FedEx and USPS side by side.
Pallet sizes and weights are in the standard pallet sizes guide.
Shipping many boxes? The pallet calculator counts boxes per pallet within a height and weight limit, and the freight class calculator gives the class of the loaded pallet for LTL.

Questions

What are standard shipping box sizes?

There is no single standard: box makers sell stock sizes by the inch. Uline’s catalog has cube boxes from 3 × 3 × 3 to 36 × 36 × 36 in and rectangular stock sizes such as 12 × 9 × 6, 16 × 12 × 8, 18 × 12 × 12 and 24 × 18 × 16 in. We found no ranking of the most common sizes from Uline, UPS or USPS.

What are the USPS Flat Rate box sizes?

Outside dimensions: Small 8-11/16 × 5-7/16 × 1-3/4 in; Medium top loading 11-1/4 × 8-3/4 × 6 in; Medium side loading 14-1/8 × 12 × 3-1/2 in; Large 12-1/4 × 12 × 6 in (USPS Domestic Mail Manual).

What is the largest box USPS accepts?

USPS accepts parcels up to 70 lb and 108 in in length and girth combined (length is the longest side, girth the distance around the thickest part); USPS Ground Advantage Commercial allows up to 130 in (DMM 201, 7.3).

Which box size gives the lowest dimensional weight?

The smallest box the item fits in. A 12 × 12 × 12 in box has a dimensional weight of 13 lb at UPS and FedEx (1,728 in³ ÷ 139, rounded up), so anything lighter than that is billed on size. Shaving an inch off each side often saves several pounds.

How many boxes fit on a pallet?

It depends on the box and the height limit. On a 48 × 40 in pallet stacked to 72 in including a 6.5 in pallet, 80 boxes of 16 × 12 × 8 in fit (10 per layer, 8 layers) and 60 boxes of 12 × 12 × 12 in. The pallet calculator works it out for any box, with a weight limit.

Are inside or outside dimensions used for shipping?

Carriers measure the outside of the package. Many box catalogs list inside dimensions (the size of what fits), so such a box sold as 12 × 12 × 12 measures a little more outside; measure the packed box before you calculate dimensional weight.

Shipping box sizes