They say good things come in small packages... but when you use Pirate Ship, USPS® and UPS® do have a minimum package size requirement!
Minimum package dimensions for USPS and UPS labels on Pirate Ship
When shipping a box, the minimum dimensions are 6x3x0.25".
If your box is smaller than that, USPS and UPS could technically reject your package... although we rarely see this happen.
It's best to use a box that's at least as big as the minimum dimensions... but if there's no way for you to do that, we recommend putting the box into a small poly mailer envelope when shipping it.
Learn more about placing boxes inside poly mailers, also known as the "Box in a Bag" method.
USPS International shipments must meet the following minimum requirements:
USPS First Class Package International
USPS First Class Package International is the cheapest international service USPS offers for packages that weight less than 4 lbs.
Boxes:
Minimum height: 4"
Tubes:
Minimum length: 8.25"
USPS First Class Package International
Priority Mail International is the Postal Service's cheapest way to ship packages that weigh more than 4 pounds internationally.
Min Length: The surface area of the address side of the item to be mailed must be large enough to completely contain the postage and customs form.
USPS Priority Mail Express International
Priority Mail Express International is the fastest way to ship internationally through the Postal Service, with delivery within 3 to 5 business days depending on the country (excluding customs processing).
Boxes:
Min Length: The surface area of the address side of the item to be mailed must be large enough to completely contain the postage and customs form.