Maximum Sizes and Weights for USPS services

Domestic Services:

First Class Package

  • Maximum Size: 22″ x 18″ x 15″ for boxes

    • 18" x 18" for envelopes or poly mailers

  • Maximum Weight: 15.99 oz 

Weight-Based Priority Mail

  • Maximum Size: 108” combined Length + Girth

  • Maximum Weight: 70 lbs (1120 ounces)

Priority Mail Cubic

  • Maximum Size: 18" in any dimension, total volume cannot exceed 0.5 cubic feet

  • Cubic Softpack Maximum Size: 36” combined Length + Width

  • Maximum Weight: 20 lbs (320 ounces)

Priority Mail Flat Rate

  • Maximum Weight: 70 lbs (1120 ounces)

Priority Mail Express

  • Maximum Size: 108” combined Length + Girth

  • Maximum Weight: 70 lbs (1120 ounces)

Parcel Select Ground

  • Maximum Size: 130” combined Length + Girth

  • Maximum Weight: 70 lbs (1120 ounces)

Priority Mail Regional Rate Box A

  • Maximum Weight: 15 lbs (240 ounces)

Priority Mail Regional Rate Box B

  • Maximum Weight: 20 lbs (320 ounces)

International Services:

First Class Package International: 

  • Maximum Size: 24″ in any dimension, 36″ combined Length + Width + Height

  • Maximum Weight: 4 lbs (64 ounces)

Simple Export Rate:

  • Maximum Size: 24″ in any dimension, 36″ combined Length + Width + Height

  • Maximum Weight: 4 lbs (64 ounces)

Priority Mail International:

  • Maximum Size: 108” combined Length + Girth

  • Maximum Weight: 70 lbs (1120 ounces)

Priority Mail International Flat Rate:

  • Maximum Weight for Flat Rate Envelope and Small Flat Rate Box: 4 lbs (64 ounces)

  • Maximum Weight for Medium and Large Flat Rate Box: 20 lbs (320 ounces)

Priority Mail Express International:

  • Maximum Size: 79” combined Length + Girth

  • Maximum Weight: 70 lbs (1120 ounces)

Size Shipping Tips:

How to Calculate Girth

To calculate the girth of your package, apply the following steps:

  1. Measure the three dimensions of your box, in inches. For example, let's say your box is 10x9x8".

  2. Add the measurements of the two smallest dimensions together (in this case, 9" plus 8" equals 17"). Multiply that number by two, and you've got the girth 👍

    In the example above, the girth of this package is 34".

Any questions? Chat with our Support Crew and we'll lend a hook 😃

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