Showing results for 
Search instead for 
Did you mean: 

This article is part of a series to give a brief overview of the different services offered by USPS through ShipStation.


USPS First-Class Package service offers the best rates for lightweight shipments for both domestic and international destinations. 



First-Class Package Service is separate from the USPS First-Class Mail service. First-Class Mail is used to send letters and Large Envelopes/Flats. 


Best  Used for: 

  • Lightweight packages - less than 1 lb - within the US and territories
  • Lightweight packages - less than 4 lbs - to international destinations


Basic Info





Delivery timeline

Domestic: averages 1-5 business days

International: Varies based on destination country. There is no guaranteed timeline.


Confirmation Options
Delivery confirmation (tracking) is free for domestic

Signature Required for an added fee

International Confirmation varies by destination country


Insurance Options

Available for both domestic and international shipments for an additional fee. Learn more about ShipStation's Insurance Options.


Rate Calculation

Domestic rates are calculated by package weight and zones.

International rates are calculated by package weight and Country Group.



Restricted Items

There are restrictions for mailing restricted, prohibited, and hazardous materials, including cigarettes and smokeless tobacco. See USPS Shipping Restrictions for up-to-date information on item limitations. 


Weight Limits

The maximum weight for domestic labels purchased through an online shipping service is less than 16 oz. 

Maximum weight for international shipments: up to 4 lbs.

Some countries may have lower weight restrictions. View Country-Specific Restrictions.


Package Dimension Limits

Maximum dimensions for domestic shipments: 23" x 18" x 15" (LxWxH)

Minimum dimensions: 5" x 3.5" x 0.007". Machinable packages may not be smaller than 6" x 3" x 0.25".


Maximum dimensions for international shipments: 24" Length, L+H+W= 36"

Learn more about USPS Dimension Measurements.

Version history
Revision #:
6 of 6
Last update:
‎03-05-2021 12:00 PM
Updated by: