If you ship packages larger than the supported size from USPS, you will receive an error: Package is too large.


Currently, there are 3 supported package types:


Package Type
Size Limit
Package
The distance of the longest side plus twice the width plus twice the height is under 85".
Large Package
The distance of the longest side plus twice the width plus twice the height is between 85" and 108".
Oversized Package
The distance of the longest side plus twice the width plus twice the height is between 109" and 130".

USPS will not accept packages greater than 130".


The "size" of a package is calculated as the Length (longest side) + 2 * Width + 2 * Height.


You can find more about USPS Package sizes and Mailpiece Types here: https://help.stamps.com/hc/en-us/articles/21473266122139-USPS-Mailpiece-Types