Package Sizes and Dimensions - USPS Domestic | Overview

ShippingEasy wants to help you learn about the e-commerce industry. This article describes service requirements set by the United States Postal Service (USPS).

The USPS is a separate organization from ShippingEasy. For more information about USPS services, visit your local Post Office or go to

Understanding the specific package sizes and dimensions for USPS services will help you make more informed decisions about how to ship your products. This guide outlines the requirements of girth, packaging, and dimensions for domestic services. By looking at each section separately, you can more accurately measure your shipment and determine what the cost will be.

Dimensions and Girth

Shipping dimensions are only used if you are sending a shipment in a custom box or envelope rather than in a carrier's flat-rate packaging. The shipment dimensions will affect the cost of the shipment, so accurate measurements are important.

Dimensional (cubic) pricing and dimensional (DIM) weight pricing are based on volume (length x width x height) rather than physical weight as the volume determines how much space the package takes up in the truck or airplane.

Length: The longest size of the package.

Width: The distance from one side to the other on the shortest part of the package.

Height: The distance from top to bottom of a standing package. 


"Machinable" packages mean they are able to be sorted by a machine. If your package is larger than the machine is able to sort, it will be bumped into the next class of letters or packages, which often costs more money.

Machinable - Oversized vs Minimum dimensions

Oversized Priority Mail packages may be subject to dimensional pricing even when below the maximum 108" dimension. Learn more about USPS oversized package charges.

Packages are also subject to minimum dimensions. No package may be smaller than 5" x 3.5" x 0.007". Machinable packages may not be smaller than 6" x 3" x 0.25". Non-machinable packages may be subject to additional handling fees. Learn more about physical standards for parcels.


When determining your package size, you may need to know the package's girth.

Girth: The width and height of a package doubled and added together


Carrier Packaging

Some domestic shipping supplies are offered for free through the USPS.

Click on the following options to order free boxes:

ShippingEasy Tools for Managing Packages

ShippingEasy offers tools to make selecting the right carrier and package even easier.

Custom Packages

If you have your own unique packaging that you use to ship your products, you can save your package size and dimension on ShippingEasy's PACKAGE SETUP page. These are for packages that are different from the normal USPS Carrier Packages. Learn more about custom packages.

Shipping Presets

Shipping Presets are saved carrier package and service types available for quick use on the ORDERS and READY TO SHIP page. ShippingEasy has 13 pre-loaded shipping presets available for use with USPS. You can also set your own. Learn more about shipping presets.

Carrier packages are available when using a compatible USPS service on the READY TO SHIP page. Learn more about selecting a carrier and package in ShippingEasy.

USPS Domestic - Standard Package Sizes and Dimensions

The following tables outline the maximum weights and dimensions for domestic package and envelope types offered through the USPS. Learn more about shipment dimensions.

Domestic Package Size Chart

Package Type Service Max Weight Max Dimensions
Package First-Class Package Service 15.9 oz 22" x 18" x 15"
Parcel Select Ground 70 lbs Length + Girth < 130"
Priority Mail 70 lbs Length + Girth < 108"
Priority Mail Express 70 lbs Length + Girth < 108"
Flat Rate Small Box Priority Mail 70 lbs 8-5/8" x 5-3/8" x 1-5/8"
Flat Rate Medium Box Priority Mail 70 lbs

Box 1= 11-1/4" x 8-3/4" x 6"

Box 2= 12" x 3-1/2" x 14-1/8"

Flat Rate Large Box Priority Mail 70 lbs 12" x 12" x 5-1/2"
Regional Rate Box A Priority Mail 15 lbs 10-15/16" x 2-3/8" x 12-13/16"
10" x 7" x 4-3/4"
Regional Rate Box B Priority Mail 20 lbs 14-3/8" x 2-7/8" x 15-7/8"
12" x 10-1/4" x 5"

Domestic Envelope Size Chart

Envelope Type Service Max Weight Max Dimensions
Letter First Class Mail 3.5 oz 11-1/2" x 1/4" x 6-1/8"
Flat Rate Envelope Priority Mail
Priority Mail Express
70 lbs 12-1/2" x 9-1/2"
Flat Rate Padded Envelope Priority Mail
Priority Mail Express
70 lbs 12.5" x 9.5"
Flat Rate Legal Envelope Priority Mail
Priority Mail Express
70 lbs 15" x 9-1/2"


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