What's the Cheapest Way to Ship with USPS?

We will be the first to admit it - shipping is complicated! One of the first questions that any online retailer faces is: what is the most cost-effective way to ship my packages? While there is no one-size-fits-all answer, we understand that controlling your bottom line is vital.

There's some pretty simple rules of thumb when it comes to knowing what will be the cheapest way to ship:

  • If your package is 15.9 ounces or less, then using your own packaging with the First Class Package service will always be cheapest.

  • If your package is over 1lb but it fits into any Flat Rate Envelope or the Small Flat Rate Box, those are the cheapest ways to go.

  • If your package is over 1lb and doesn't fit into those, then it's cheapest to use as small of a box as possible to qualify for Priority Mail Cubic.

  • Only if your package weighs more than 20lbs would Medium or Large Flat Rate Boxes ever be a good deal. Regional Rate Boxes are never a good deal.

Related: How to Get Free Shipping Supplies from USPS, UPS, FedEx, and DHL

One benefit of Priority Mail Cubic is you can use your own packaging, but USPS also offers free boxes you can use with Priority Mail Cubic:

Priority Mail Box - 1096L | OD: 9-7/16" x 6-7/16" x 2-3/16" | Cubic Tier 1

Priority Mail Box - 4 | OD: 7-1/4" x 7-1/4" x 6-1/2" | Cubic Tier 2

Priority Mail Box - 1097 | OD: 11.625" x 2.5" x 13.4375" | Cubic Tier 3

Priority Mail Box - 1092 | OD: 12.25" x 2.875" x 13.6875" | Cubic Tier 3

Priority Mail Box - 1095 | OD: 12.5" x 3.125 x 15.375" | Cubic Tier 4

Priority Mail Box - Shoe Box | OD: 7-3/8" x 5-1/4" x 14-7/8" | Cubic Tier 4

Learn More: USPS First Class Package and Other USPS Mail Classes