Does USPS Charge by Weight or Size? (2022 Facts)

Does USPS charge by weight or size? There are many different ways to send a package. You can use UPS, FedEx, the United States Postal Service, or any other carriers. But have you ever taken your package to the post office and been shocked by how expensive it is? The good news is that the price of shipping usually depends on the weight of your package, not its size.

does USPS charge by weight or size

USPS Overview

The United States Postal Service (USPS) is an independent agency of the executive branch of the United States federal government responsible for providing postal service in the United States, including its insular areas and associated states. It is one of the few government agencies explicitly authorized by the United States Constitution.

The USPS has exclusive access to letterboxes marked "U.S. Mail" and personal letterboxes in the United States and handles more than 160 billion pieces of mail per year. The USPS is the third-largest employer in the United States behind Walmart, with over 617,000 employees as of 2019. The U.S. Post Office Department was created on July 26, 1775, by decree of the Second Continental Congress; Benjamin Franklin served as the first Postmaster General. The American Revolution delayed the establishment of the postal service until 1792 when Major General George Washington signed the Postal Service Act establishing the Department of the Post Office.

Does USPS charge by weight or Size?

The United States Postal Service will most likely continue to charge based on weight and distance.

However, some services may apply dimensional weight pricing if the parcel exceeds size limits. Dimensional weight pricing factors in length, height, and width. Some services offer convenient flat-rate shipping for parcels up to 70 lbs.

The USPS offers a variety of shipping options to choose from, so customers can find the best option for their needs. With flat-rate shipping, customers know exactly how much their shipping will cost, regardless of the weight or size of their parcel.

For packages that are heavier or larger than the limit for flat-rate shipping, the USPS offers several other options that may be more affordable. Customers can compare prices and find the option that best meets their needs.

What is the cost per pound of USPS shipping?

The cost per pound to ship a package via USPS is determined by the form of USPS shipping service you pick and the distance your goods will travel. Parcels may be sent using First-Class Package Service-Retail, Ground, Priority Mail, and Priority Mail Express.

If the size maximum has been exceeded, four of these can utilize DIM (Dimensionally Weighted Average). The length x width x height ÷ 166 is used to calculate DIM.

The below shows the cost per pound for each shipping choice:

First-Class Package Service-Retail

  • First-Class Package Service is for smaller packages, less than 13 oz.
  • Packages generally take between 1 and 3 business days
  • Prices start at $4 for 1 oz., rising to $6.25 for 13 oz.

Retail Ground

  • This service includes USPS tracking and is a good alternative when packages are too large for Priority Mail and Priority Express
  • Limits to Retail Ground include 70 lbs. of weight and 130 inches in combined length and girth
  • Prices start at $7.70 for one pound and climb to $49 for 70 lbs.

Priority Mail

  • This service is the “next step up” from First Class shipping
  • It is slightly faster (1-3 business days), can deliver on Sundays (for an additional fee), and includes shipping of letters, large envelopes, and parcels
  • Parcels must be 70 lbs. or less, with a max of 108 inches in combined length and girth
  • Prices start at $7.70 for one pound, all the way up to $49 for 70 lbs.
  • This service also includes Flat Rate shipping, which starts at $7.95 for envelopes, $8.45 for small boxes, $15.50 for medium, and $21.90 for large

Priority Mail Express

  • This service is the fastest and includes next-day and 2-day shipping on letters, envelopes, and parcels
  • Parcels must be 70 lbs. or less, with a combined length and girth of 108 inches max
  • Prices start at $26.35 for a half-pound and climb to $184.30 for 70 lbs.
  • Priority Express also offers flat-rate envelopes, which range from $22.75 to $23.25

Parcel Select

  • This service is for regular shippers who don’t need to get their parcels anywhere in a hurry and who want the cheapest shipping rates
  • The weight limit is 70 lbs. and the size limit is 108 inches in length and girth combined
  • Prices start at just $3.30 for one pound; the price for a 70-lb. package starts at only $9.24.

Which is cheap UPS or USPS for sending a box?

If you're shipping something small and lightweight, it's almost always going to be cheaper to use the United States Postal Service. That being said, there are certain circumstances where it might make more sense to use UPS or FedEx. For example, if you're shipping something very heavy, USPS won't be an option since they have a weight limit of 70 lbs.

Additionally, if you need your shipment to arrive quickly, USPS might not be the best choice since they don't guarantee delivery times the way UPS and FedEx do. So when deciding which shipping company to use, it's important to consider factors like weight, speed, and price. Only then will you be able to make the best decision for your specific needs.

Is it cheaper to ship USPS with your own box?

When it comes to shipping via USPS, there are a few things to consider in regards to cost. If you have an item that weighs less than one pound, First-Class Package Service is typically the cheapest option. However, if you have a heavier item, say 60 pounds, and it will fit in a USPS Priority Mail Flat-Rate box, that option becomes more cost effective.

The Priority Mail Flat-Rate box is free of charge (you can pick one up at any post office lobby) and the flat rate for a large box is only $21.90. Shipping a 60-pound item in your own box starts at $42.90 but could potentially increase up to $277.15 depending on the distance it needs to travel. Therefore, if you have a heavier item to ship and are able to use a USPS Priority Mail Flat-Rate box, it is cheaper to ship with your own box rather than using a USPS shipping container.

Is it legal to use a Personal Box for USPS Flat Rate?

The answer is no - if you want to use USPS's flat rate shipping options, you must use one of their approved boxes. This includes their three different sizes of boxes (as well as a few different envelope options). While it may be more convenient to use your own box, USPS requires that you use one of their approved boxes in order to take advantage of their flat rate shipping services.

If you need more information on which size box to choose, you can visit this page here. Otherwise, keep in mind that you can use your own box for any other shipping service besides USPS's flat rate shipping services.


The United States Postal Service (USPS) is a reliable and affordable shipping option for packages of all sizes. The USPS website provides a shipping calculator to help customers estimate the cost of shipping their items. Most commonly, the USPS uses weight and distance to calculate shipping costs.

However, if a package exceeds size limits, weight, size, and distance may come into play. The USPS also offers Priority Mail flat rate shipping, which is often much cheaper than alternatives like UPS or FedEx. For customers looking to save money on shipping, the USPS is a great option.

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