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USPS Priority Mail: Weight Rates vs Cubic (dimensional)

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ShippingEasy Content Team

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In this guide, we compare specific USPS Priority Mail services: weight-based rates and cubic dimensional rates. To make a comparison using this guide, you will need accurate weight and dimensions of the package you want to ship.

Before comparing rates, it is best to determine if your packages qualify for cubic rates. Learn more about cubic dimensional pricing.

Comparing Weight-Based Service and Cubic (dimensional)

With either weight-based services and cubic dimensional rates, shippers use their own packaging.

Weight-based Dimensions

Weight-based services offer the most flexibility. With minimal restrictions, package girth may not exceed 108" inches and the total weight must be less than 70 lbs. As the name indicates, weight is a factor in determining postage costs.

Cubic Dimensions

In the case of cubic, specific package restrictions apply:

  • Weigh less than 20 lbs

  • Volume may not exceed 0.50 cu ft

  • No dimension longer than 18 inches

Cubic rates are based on package dimensions. By keeping packaging small, larger discounts are available. A tiered system is used to define package dimensions:

  • Tier 1: less than 0.10 cu ft

  • Tier 2: less than 0.20 cu ft

  • Tier 3: less than 0.30 cu ft

  • Tier 4: less than 0.40 cu ft

  • Tier 5: less than 0.50 cu ft

Zone

Both rates rely on zone-based pricing, meaning that rates increase as the distance (zone) increases. Learn more about USPS zones.

In general, you'll see the greatest advantage with weight-based rates for very-light, very-heavy, or very-large packages. In most other cases the dimensional rates will be lower. If package dimensions are entered, ShippingEasy will always quote the lower rate between the weight-based rate and cubic dimensional.

Detailed Service Comparisons

The tables below provide a visual summary of when it's best to enter dimensions for cubic or weight-based service, based on weight and zone.

To simplify the data, we use a color and letter code to indicate the best packaging. Please keep in mind that the services listed are only the best value when your products will fit into the defined package dimensions. Use the legend below to read the following charts.

Table Legend

Priority Mail Service

Code

Packaging

Cubic

1

Tier 1, only

2

Tier 1 or 2

3

Tier 1, 2, or 3

4

Tier 1, 2, 3, or 4

5

Tier, 1, 2, 3, 4, or 5

Weight-based

W

Any package less than 108" girth

Weight-Based Service - vs - all Cubic Tiers

In nearly all cases, if you ship small packages weighing less than 20 lbs, you will get a better rate with cubic by entering package dimensions.

The greatest advantages come when shipping further, to Zones 8-9. In this case, even Tier 5 shipments (less than 0.5 cubic feet) weighing more than 6 lbs ship for less under cubic.

If package dimensions are entered, ShippingEasy will always quote the lower rate between the weight-rate and cubic.

Weight-Based Service - vs - all Cubic Tiers Commercial Prices by Zone

Weight Not Over (Lbs)

Zones 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

0.5

3

4

4

3

3

1

1

W

W

1

3

4

4

3

3

1

1

W

W

2

5

5

5

4

4

2

2

2

2

3

5

5

5

5

5

3

3

3

3

4

5

5

5

5

5

3

3

3

3

5

5

5

5

5

5

4

4

4

4

6

5

5

5

5

5

5

5

5

5

7

5

5

5

5

5

5

5

5

5

8

5

5

5

5

5

5

5

5

5

9

5

5

5

5

5

5

5

5

5

10

5

5

5

5

5

5

5

5

5

11

5

5

5

5

5

5

5

5

5

12

5

5

5

5

5

5

5

5

5

13

5

5

5

5

5

5

5

5

5

14

5

5

5

5

5

5

5

5

5

15

5

5

5

5

5

5

5

5

5

16

5

5

5

5

5

5

5

5

5

17

5

5

5

5

5

5

5

5

5

18

5

5

5

5

5

5

5

5

5

19

5

5

5

5

5

5

5

5

5

20

5

5

5

5

5

5

5

5

5

Weight-Based Service - vs - Cubic Tier 1

When your products fit into a package that is smaller than 0.1 cubic feet, enter your package dimensions to get the best rate.

In most cases, cubic tier 1 will be the most cost-effective option for shipping packages. For packages under 2 lbs traveling far distances, weight-based services offer the best rates.

If package dimensions are entered, ShippingEasy will always quote the lower rate between the weight-rate and cubic.

Weight-Based Service - vs - Cubic Tier 1 Commercial Prices by Zone

Weight Not Over (Lbs)

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

0.5

1

1

1

1

1

1

1

W

W

1

1

1

1

1

1

1

1

W

W

2

1

1

1

1

1

1

1

1

1

3

1

1

1

1

1

1

1

1

1

4

1

1

1

1

1

1

1

1

1

5 and up

1

1

1

1

1

1

1

1

1

Weight-Based Service - vs - Cubic Tier 2

When your products fit into a package that is smaller than 0.2 cubic feet, enter your package dimensions to get the best rate.

Packages weighing more than 2 lbs will get the best price through the cubic rate. Any packages weighing more than 20 lbs will not qualify for cubic rates.

Shipments weighing between 1 lbs and 2 lbs will see the best service change based on distance traveled. The advantage shifts from cubic to weight-rates with increasing Zone. Cubic offers the best price for shipments 1-2 lbs destined for Zones 6-9.

Weight-Based Service - vs - Cubic Tier 2 Commercial Prices by Zone

Weight Not Over (Lbs)

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

0.5

2

2

2

2

2

W

W

W

W

1

2

2

2

2

2

W

W

W

W

2

2

2

2

2

2

2

2

2

2

3

2

2

2

2

2

2

2

2

2

4

2

2

2

2

2

2

2

2

2

5

2

2

2

2

2

2

2

2

2

6

2

2

2

2

2

2

2

2

2

7

2

2

2

2

2

2

2

2

2

8

2

2

2

2

2

2

2

2

2

9

2

2

2

2

2

2

2

2

2

10 and up

2

2

2

2

2

2

2

2

2

Weight-Based Service - vs - Cubic Tier 3

When your products fit into a package that is smaller than 0.3 cubic feet, enter your package dimensions to get the best rate.

Packages weighing more than 3 lbs will get the best price through the cubic rate. Any packages weighing more than 20 lbs will not qualify for cubic.

Shipments weighing between 1 lbs and 3 lbs will see the best service change based on distance traveled. The advantage shifts from cubic to weight-rates with increasing Zone. Cubic offers the best price for shipments over 3 lbs destined for Zones 1-5.

If package dimensions are entered, ShippingEasy will always quote the lower rate between the weight-rate and cubic.

Weight-Based Service - vs - Cubic Tier 3 Commercial Prices by Zone

Weight Not Over (Lbs)

Zone1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

0.5

3

3

3

3

3

W

W

W

W

1

3

3

3

3

3

W

W

W

W

2

3

3

3

3

3

W

W

W

W

3

3

3

3

3

3

3

3

3

3

4

3

3

3

3

3

3

3

3

3

5

3

3

3

3

3

3

3

3

3

6

3

3

3

3

3

3

3

3

3

7

3

3

3

3

3

3

3

3

3

8

3

3

3

3

3

3

3

3

3

9

3

3

3

3

3

3

3

3

3

10

3

3

3

3

3

3

3

3

3

11

3

3

3

3

3

3

3

3

3

12

3

3

3

3

3

3

3

3

3

13

3

3

3

3

3

3

3

3

3

14

3

3

3

3

3

3

3

3

3

15 and up

3

3

3

3

3

3

3

3

3

Weight-Based Service - vs - Cubic Tier 4

When your products fit into a package that is smaller than 0.4 cubic feet, enter your package dimensions to get the best rate.

Packages weighing more than 4 lbs will get the best price through the cubic rate. Any packages weighing more than 20 lbs will not qualify for cubic.

Shipments weighing between 1lbs and 4 lbs will see the best service change based on distance traveled. The advantage shifts from weight-rates to cubic with increasing Zone. Cubic offers the best price for shipments 1-4 lbs destined for Zones 1-5.

If package dimensions are entered, ShippingEasy will always quote the lower rate between the weight-rate and cubic.

Weight-Based Service - vs - Cubic Tier 4

Weight Not Over (Lbs)

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

0.5

W

W

4

W

W

W

W

W

W

1

W

W

4

W

W

W

W

W

W

2

4

4

4

4

4

W

W

W

W

3

4

4

4

4

4

W

W

W

W

4

4

4

4

4

4

W

W

W

W

5

4

4

4

4

4

4

4

4

4

6

4

4

4

4

4

4

4

4

4

7

4

4

4

4

4

4

4

4

4

8

4

4

4

4

4

4

4

4

4

9

4

4

4

4

4

4

4

4

4

10

4

4

4

4

4

4

4

4

4

11

4

4

4

4

4

4

4

4

4

12

4

4

4

4

4

4

4

4

4

13

4

4

4

4

4

4

4

4

4

14

4

4

4

4

4

4

4

4

4

15 and up

4

4

4

4

4

4

4

4

4

Weight-Based Service - vs - Cubic Tier 5

When your products fit into a package that is smaller than 0.5 cubic feet, enter your package dimensions to get the best rate.

Packages weighing more than 5 lbs will get the best price through the cubic rate. Any packages weighing more than 20 lbs will not qualify for cubic.

Shipments weighing between 1 lbs and 5lbs will see the best service change based on distance traveled. The advantage shifts from weight-rates to cubic with increasing Zone.  Cubic offers the best price for shipments over 2-3 lbs destined for Zones 1-3.

If package dimensions are entered, ShippingEasy will always quote the lower rate between the weight-rate and cubic.

Weight-Based Service - vs - Cubic Tier 5

Weight Not Over (Lbs)

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

0.5

W

W

W

W

W

W

W

W

W

1

W

W

W

W

W

W

W

W

W

2

5

5

5

W

W

W

W

W

W

3

5

5

5

5

5

W

W

W

W

4

5

5

5

5

5

W

W

W

W

5

5

5

5

5

5

W

W

W

W

6

5

5

5

5

5

5

5

5

5

7

5

5

5

5

5

5

5

5

5

8

5

5

5

5

5

5

5

5

5

9

5

5

5

5

5

5

5

5

5

10

5

5

5

5

5

5

5

5

5

11

5

5

5

5

5

5

5

5

5

12

5

5

5

5

5

5

5

5

5

13

5

5

5

5

5

5

5

5

5

14

5

5

5

5

5

5

5

5

5

15 and up

5

5

5

5

5

5

5

5

5

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