Is there a Minimum Package Size to Ship with USPS?

If you’re using shipping software to buy labels for tiny products like toys or figurines with USPS, then you may have noticed some packages are too small for USPS to accept. In this case, you’ll simply need to enter a different size when purchasing postage in order to meet the minimum package size guidelines.

Table of Contents

• The Minimum Size Depends on Your Package
• Is There a Maximum Size?
• Be Aware of USPS Non-Standard Fees

The Minimum Size Depends on Your Package

According to the USPS Postal Explorer, the minimum package size is at least 6 inches in length, 3 inches in height, and 1/4 of an inch in thickness. Written out in decimal points, that size is: 6 x 3 x 0.25″.

This means that two sides of your package need to be entered in as at least 6 inches, and 3 inches (respectively).  If your package is actually smaller, we suggest just entering the minimum dimensions anyway when making your label. This way, you’re able to purchase a label and get to shipping. We’ve hardly ever seen USPS reject a slightly smaller. package because of this…though discretion does vary from Post Office to Post Office.

Is There a Maximum Size?

Just like there is a minimum size or shipping with USPS, there’s also a maximum size for each mail class. In fact, USPS is much stricter about the maximum package sizes, since their trucks don’t have that much excess capacity for larger boxes and envelopes.

Here are the maximum dimensions for First Class Package and Priority Mail, two of the Postal Service’s most popular shipping options:

• First Class Package:  22  x 18 x 15″
• Priority Mail: Maximum Length + Girth of 108 inches

Learn more about the maximum box dimensions USPS allows, and how to calculate the girth of your package.

Be Aware of USPS Non-Standard Fees

For some shipments, USPS imposes fees called “Non-Standard Package Fees” on most of their domestic shipping services in situations when the boxes are bigger than certain dimensions.

The shipping services where these fees apply are Parcel Select Ground, Priority Mail, and Priority Mail Express. USPS doesn’t apply any non-standard fees to First Class Package and Media Mail shipments, on the other hand.

Here’s a breakdown of those fees and the situations when they apply:

Parcel Select Ground shipments

• $4 if any length of your package exceeds 22 inches but is less than or equal to 30 inches
• $7 if any length of your package exceeds 30 inches
• $15 for packages greater than 2 cubic feet in volume
• $1.50 for missing or incorrect dimensions that result in any of the above non-standard surcharges

Priority Mail and Priority Mail Express shipments

• $4 if any length of your package exceeds 22 inches but is less than or equal to 30 inches
• $15 if any length of your package exceeds 30 inches
• $25 for packages greater than 2 cubic feet in volume
• $1.50 for missing or incorrect dimensions that result in any of the above non-standard surcharges

Read more about USPS non-standard fees and whether or not your shipments will be impacted.