USPS Shipping Rates Explained

One of the biggest decisions a business owner makes is choosing the right carrier. USPS provides shippers with multiple, affordable carrier services, so customers can receive orders within a needed time frame. Additionally, our research showed that 41% of customers consider shipping cost to be the most important factor when shopping online. The savings on shipping costs through USPS will be passed down to customers, helping your business align with current ecommerce expectations. 

What are USPS shipping rates?

USPS domestic shipping rates are divided into two categories: Retail rates and Commercial rates. Retail rates are the prices given to shippers who purchase postage directly from USPS. Commercial rates are pre-negotiated prices available to shippers who use ShipEngine. 

Available USPS shipping options 

USPS offers multiple carrier services with tracking and insurance options, so orders can arrive to customers safely and securely. We’ve crafted a table with some of the most commonly used USPS services and features for easy comparison and selection. 

*Note: Media Mail^® can only be used for certain products, including books, test materials, CDs, and DVDs. A full list of products eligible for Media Mail^® can be found on the USPS website.

Factors that impact USPS shipping rates 

The shipping cost of a shipment will vary, depending on the shipment’s dimensions, the carrier service selected, and the distance the shipment is traveling. USPS rounds dimensions up to the nearest pound or inch, so enter rounded dimensions when calculating the shipping cost for the most accurate rates. Additionally, a shipment can be charged by actual weight or Dimensional (DIM) weight, so it’s beneficial to understand the difference between the two. 

DIM weight vs actual weight 

When a package is shipped through USPS, the billable weight can be the weight seen on a scale or a calculation of weight based on volume. The actual weight of a shipment is the number shown when a package is placed directly on the scale. The DIM weight of a shipment is calculated by finding a shipment’s volume (length x width x height).

If a shipment’s volume is under 1,728 cubic inches, the shipment will be charged by its actual weight. If a shipment’s volume is over 1,728 cubic inches, use the steps below to determine the weight that will be used in calculating the shipping cost. 

• Divide the shipment’s volume by 166 
• Compare this number to the shipment’s actual weight 
• The higher number will be used as the shipment’s billable weight 

USPS Zones

USPS has divided the US into nine zones. Each zone encompasses a range of mileage between the sender and recipient, and the shipping cost will change with the distance a shipment is traveling, as each zone has its own pricing tier. The USPS zones are classified as follows: 

• Zone 1: Non-local destinations within 50 miles 
• Zone 2: Destinations within 51-150 mile radius 
• Zone 3: Destinations within 151-300 mile radius 
• Zone 4: Destinations within 301-600 mile radius 
• Zone 5: Destinations within 601-1000 mile radius 
• Zone 6: Destinations within 1001-1400 mile radius 
• Zone 7: Destinations within 1401-1800 mile radius 
• Zone 8: Destinations within 1801 mile radius or farther 
• Zone 9: Destinations within Freely Associated States/Zipcodes assigned for exceptional network circumstances*

USPS also provides shippers with a free Domestic Zone Chart to help determine zones. 

*This doesn’t apply when shipping to between the three-digit zip codes of 962-969.

How to save money on USPS shipping 

• Order free supplies from USPS for applicable services
• Compare USPS services to find the best shipping rates for your business  
• Use ShipEngine to save up to 89% off Retail rates and up to 15% off Commercial Plus Pricing (CPP)