What is USPS Cubic Pricing?
Most shippers assume USPS® rates are determined primarily by package weight - but that's not always the case. USPS® offers a little-known pricing model called cubic pricing that can significantly reduce shipping costs for small but heavy items by charging based on package size rather than the physical weight. Available through services such as USPS Priority Mail® and USPS Ground Advantage™, this pricing structure rewards efficient packaging and can create cost savings for businesses of all sizes. In this guide, we'll explain how cubic pricing works, which USPS® services support it, and how to determine when it makes sense for your shipments.
So what exactly is USPS Cubic Pricing?
USPS Cubic Pricing is a shipping rate structure that determines postage based on a package's volume rather than its weight. Instead of paying more as a package gets heavier, qualifying shipments are assigned to a cubic tier based on their overall size.
This approach was designed to provide lower shipping costs for heavy, yet compact packages that would otherwise be expensive to ship using traditional weight-based rates. As long as a package meets the service requirements and falls within the maximum cubic dimensions, the actual weight of the package becomes less important.
How is it calculated?
This is the Basic formula for calculating a packages cubic foot value.
Cubic Feet = (length x Width x Height) / 1,728
Example = (12 x 8 x 6) / 1,728 = 0.333 cu ft.
(cu ft = cubic feet)
This cubic calculation will determine if the package falls inside USPS cubic rating, and if so, what rate is paid based on that value. Detailed below are the parameters for using cubic pricing for both USPS Priority Mail® as well as USPS Ground Advantage™.
Rule
Priority Mail Cubic
Ground Advantage Cubic
Max. physical package weight
20 lb
20 lb
Max. cubic foot rating
0.50 cu ft
1.00 cu ft
Longest dimension length
18 in
18 in
Cubic tier range
0.10 - 0.50 cu ft
0.10 - 1.00 cu ft
Rule
Priority Mail Cubic
Max. physical package weight
20 lb
Max. cubic foot rating
0.50 cu ft
Longest dimension length
18 in
Cubic tier range
0.10 - 0.50 cu ft
Ground Advantage Cubic
Max. physical package weight
20 lb
Max. cubic foot rating
1.00 cu ft
Longest dimension length
18 in
Cubic tier range
0.10 - 1.00 cu ft
** Cubic pricing is only available through USPS Ground Advantage™ and Priority Mail® **
Cubic Pricing - Example Use Case
Let’s explore an example of when using Cubic Pricing can save you money.
An automotive business needs to ship a car part that weighs 12lbs and is going to zone 5. The part is heavy, but compact and is placed into a 10 x 8 x 4 box. Using the calculation shown above this package is 0.185 cubic feet. When rounded up, this package is 0.20 cubic feet. Using the tables below, this package would cost $9.37 which is the 0.20 cubic feet price when sending to zone 5 for USPS Ground Advantage™.
Using the same example but assume that the box is 12 x 10 x 10 and still has a physical weight of 12lbs. The package now has a cubic rating of 0.694 cubic feet. When rounded up, the package is 0.70 cubic feet. In this scenario the package would cost $14.76. Even though the package is going to the same zone, using the same service, with the same weight, the price difference is driven by the dimensions of the package.
What Services Does Cubic Pricing Apply to?
As mentioned earlier in the article, cubic pricing is only available through USPS Ground Advantage™ and USPS Priority Mail® and specifically for Commercial or NSA rates (discounted rates below retail pricing). Below are the pricing tables showing the cubic feet range, and applicable price based on the calculation for both services.
USPS Ground Advantage Cubic Price Chart
Commercial Parcels - Cubic
Cubic Feet Range Up To:
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8 & 9
0.10
7.45
7.51
7.83
7.99
8.49
9.21
9.53
10.13
0.20
7.82
7.89
8.14
8.34
9.37
10.66
11.05
11.84
0.30
8.39
8.45
8.81
9.23
10.96
12.83
13.48
14.67
0.40
9.07
9.13
9.51
10.34
12.43
14.66
15.61
17.29
0.50
9.59
9.66
10.03
10.93
13.32
15.70
16.89
18.90
0.60
9.84
9.90
10.31
11.43
14.10
16.68
18.05
20.36
0.70
9.94
10.00
10.56
11.82
14.76
17.47
19.02
21.57
0.80
10.08
10.23
11.34
12.34
15.39
18.22
19.94
22.71
0.90
10.84
11.08
12.24
13.44
16.01
18.99
20.84
23.89
1.00
12.02
12.34
13.28
14.54
16.93
20.11
22.18
25.60
Commercial Parcels - Cubic
Cubic Feet Range Up To
0.10
Zone 1
7.45
Zone 2
7.51
Zone 3
7.83
Zone 4
7.99
Zone 5
8.49
Zone 6
9.21
Zone 7
9.53
Zone 8 & 9
10.13
0.20
Zone 1
7.82
Zone 2
7.89
Zone 3
8.14
Zone 4
8.34
Zone 5
9.37
Zone 6
10.66
Zone 7
11.05
Zone 8 & 9
11.84
0.30
Zone 1
8.39
Zone 2
8.45
Zone 3
8.81
Zone 4
9.23
Zone 5
10.96
Zone 6
12.83
Zone 7
13.48
Zone 8 & 9
14.67
0.40
Zone 1
9.07
Zone 2
9.13
Zone 3
9.51
Zone 4
10.34
Zone 5
12.43
Zone 6
14.66
Zone 7
15.61
Zone 8 & 9
17.29
0.50
Zone 1
9.59
Zone 2
9.66
Zone 3
10.03
Zone 4
10.93
Zone 5
13.32
Zone 6
15.70
Zone 7
16.89
Zone 8 & 9
18.90
0.60
Zone 1
9.84
Zone 2
9.90
Zone 3
10.31
Zone 4
11.43
Zone 5
14.10
Zone 6
16.68
Zone 7
18.05
Zone 8 & 9
20.36
0.70
Zone 1
9.94
Zone 2
10.00
Zone 3
10.56
Zone 4
11.82
Zone 5
14.76
Zone 6
17.47
Zone 7
19.02
Zone 8 & 9
21.57
0.80
Zone 1
10.08
Zone 2
10.23
Zone 3
11.34
Zone 4
12.34
Zone 5
15.39
Zone 6
18.22
Zone 7
19.94
Zone 8 & 9
22.71
0.90
Zone 1
10.84
Zone 2
11.08
Zone 3
12.24
Zone 4
13.44
Zone 5
16.01
Zone 6
18.99
Zone 7
20.84
Zone 8 & 9
23.89
1.00
Zone 1
12.02
Zone 2
12.34
Zone 3
13.28
Zone 4
14.54
Zone 5
16.93
Zone 6
20.11
Zone 7
22.18
Zone 8 & 9
25.60
USPS Priority Mail Cubic Price Chart
Cubic Feet Rang Up To:
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
0.10
9.06
9.34
9.73
10.50
13.02
14.69
15.39
15.51
33.09
0.20
9.10
9.39
9.78
10.79
13.17
15.34
16.31
16.37
34.94
0.30
9.45
9.71
10.75
12.68
16.56
18.86
20.51
20.57
43.91
0.40
11.06
11.29
12.63
15.12
20.23
24.88
27.25
27.30
58.28
0.50
11.59
11.70
13.23
16.10
22.31
27.27
30.24
30.56
65.23
Cubic Feet Range Up To
0.10
Zone 1
9.09
Zone 2
9.34
Zone 3
9.73
Zone 4
10.50
Zone 5
13.02
Zone 6
14.69
Zone 7
15.39
Zone 8
15.51
Zone 9
33.09
0.20
Zone 1
9.10
Zone 2
9.39
Zone 3
9.78
Zone 4
10.79
Zone 5
13.17
Zone 6
14.69
Zone 7
15.39
Zone 8
16.37
Zone 9
34.94
0.30
Zone 1
9.45
Zone 2
9.71
Zone 3
10.75
Zone 4
12.68
Zone 5
16.56
Zone 6
18.86
Zone 7
20.51
Zone 8
20.57
Zone 9
43.91
0.40
Zone 1
11.06
Zone 2
11.29
Zone 3
12.63
Zone 4
15.12
Zone 5
20.23
Zone 6
24.88
Zone 7
27.25
Zone 8
27.30
Zone 9
58.28
0.50
Zone 1
11.59
Zone 2
11.70
Zone 3
13.23
Zone 4
16.10
Zone 5
22.31
Zone 6
27.27
Zone 7
30.24
Zone 8
30.56
Zone 9
65.23
Summary
To summarize, USPS Cubic Pricing helps rewards shippers who ensure their items are placed in the correct size packaging. It also brings affordable price structures to items that are heavier in weight but smaller in size. This system benefits the USPS® as right sized packaging helps maximize the number of packages that can be loaded onto a truck or plane for delivery.
For more information on the importance of selecting the correct parcel size, you can read our newsroom article Are you overlooking these costly shipping mistakes? Or you can watch the video below.
Cubic Pricing FAQs
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Published at: 07/22/2026
Lucas Bingham is the Product and Business Development Specialist at FP Mailing Solutions. He has been with FP since 2017 and spends the bulk of his time working on FP’s digital solutions. When not at work Lucas enjoys being outside and spending time with his wife and two puppies, Clark and Nova.
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