Key Points:

  • USPS offers free shipping boxes to match most of its shipping services, though you'll have to pay for USPS Forever Prepaid Flat Rate boxes
  • Order USPS boxes online or from your local post office
  • Easyship saves you up to 91% off discounted USPS shipping rates with our Free Shipping Rates Calculator

The United States Postal Service (USPS) offers a range of shipping boxes to match its shipping services, including:

  • USPS Flat Rate boxes
  • USPS Regional Rate boxes
  • USPS Forever Prepaid Flat Rate boxes

Choosing the right USPS boxes is part of getting the cheapest rates on USPS shipping. Fortunately, most USPS boxes are free for order on the USPS website.

Want to use your own boxes for USPS shipments? You can, except with Flat Rate shipping. Flat Rate shipping must use USPS Flat Rate boxes. Read this blog to learn the ins and outs of which USPS box is right for your next shipment.

Easyship can help you save up to 70% on USPS shipments, no matter what type of box you use. This is because Easyship gives you access to the Commercial Plus Pricing rates from USPS.

You can use this article to learn about the different USPS boxes, the costs, and the shipping options they work with.

Table of Contents

3 Types of USPS Boxes

Check out these three types of USPS boxes to use for packaging your items!

USPS Flat Rate Boxes

USPS Flat Rate is a shipping option that charges a single fixed price for delivery to anywhere in the US. Unlike most shipping options, Flat Rate prices aren’t based on weight. This means a USPS Flat Rate box or envelope is often the cheapest way to ship heavy items over long distances.

To ship with USPS Flat Rate, you need to use USPS Flat Rate boxes.

Flat Rate boxes come in three main sizes: small, medium, and large. Flat Rate packaging is also available as:

  • Envelopes
  • Padded envelopes
  • Boardgame boxes
  • Military shipping boxes (APO/DPO)

As long as your item fits in any Flat Rate packaging, it can be shipped via Flat Rate for a predetermined rate to anywhere in the US.

You can order USPS Flat Rate boxes on the USPS website for free. They come in orders of 10 or 25. The list below shows the prices and dimensions of all USPS Flat Rate boxes:

  • Flat Rate Envelope: 12 ½” x 9 ½”
  • Legal Flat Rate Envelope: 15” x 9 ½”
  • Padded Flat Rate Envelope: 12 ½” x 9 ½”
  • Small Flat Rate Box: 8 11/16” x 5 7/16” x 1 ¾”
  • Top-Loading Medium Flat Rate Box – 1: 11 ¼” x 8 ¾” x 6”
  • Side-Loading Medium Flat Rate Box – 2: 14” x 12” x 3 ½”
  • Large Flat Rate Boxes: 12 ¼” x 12 ¼” x 6”

Small USPS Flat Rate boxes start at $8.45 (unless you have a commercial account) and are ideal for shipping a smartphone-sized item. On the top end, large USPS Flat Rates boxes start at $21.90 and can hold laptop-sized items. Shipping smaller items? You’ll save money by using a Flat Rate envelope.

Since envelopes aren’t sturdy, they’re only suitable for items already encased in protective packaging or aren’t prone to breakage. Here’s a list of the USPS Flat Rate envelopes available, plus examples of what can fit inside each envelope.

Flat Rate is often the cheapest way to get your item to its destination, especially for heavier packages. Flat Rate boxes or envelopes are required for shipping with USPS Flat Rate.


USPS Regional Rate Boxes

Regional Rate is a USPS shipping service that determines the shipping rate by the shipment’s distance to the destination.

Prices for Regional Rate correspond to a regional area, or “zone,” and are available for both domestic and international shipping. Generally, Regional Rate can be the cheapest way to send small shipments over a short distance.

USPS Regional Rate boxes are free if you order them online from USPS. However, if you show up at your local Post Office and request Regional Rate boxes, you’ll have to pay extra for the boxes. In general, it's best to order your USPS boxes online and have them delivered.

USPS Regional Rate boxes come in three sizes by weight:

  • Regional Rate Box A (up to 15 pounds)
  • Regional Rate Box B (up to 20 pounds)
  • Regional Rate Box C (up to 25 pounds)

Two variants of USPS Regional Rate boxes are available: side-loading or top-loading. Regional Rate prices start at $5.32 for Box A and run up to $15.25 for Box C.

To ship with USPS Regional Rate boxes, you need to use the Regional Rate shipping service. However, you can also use your own packaging for Regional Rate. To get the cheapest rates on USPS Regional, you’ll need to use USPS Priority Mail Cubic – which assesses the rate price by package dimensions instead of weight. While this sounds confusing, all you really need to know is that you’ll get different rates on using different packaging for Regional Rate.

USPS Forever Prepaid Flat Rate Boxes

Forever Prepaid is a variant of USPS Flat Rate. Just like regular Flat Rates, Forever Prepaid Flat Rate shipments can be sent to any US destination for one flat price.

The difference with Forever Prepaid is that you can buy these USPS boxes and have them function as prepaid postage – without any expiration date.

So long as you own a Forever Prepaid Flat Rate box, and your item doesn’t exceed the Flat rate weight limit – you can ship the box without any worry that it meets postage requirements.

The benefit of USPS Prepaid Boxes is that they aren’t subject to future rate increases, which happen occasionally. So even if rates go up, you can use Forever Prepaid. But since USPS Forever Prepaid Flat Rate includes your return address, the packages won’t work if you move locations.

Unlike Flat Rate and Regional Rate boxes, USPS Prepaid boxes aren’t free. You can order them online at or at the local post office. The list below details the different USPS Priority Mail Forever Box types available:

  • Priority Mail Forever Prepaid Legal Flat Rate Envelope
  • Priority Mail Forever Prepaid Padded Flat Rate Envelope
  • Priority Mail Forever Prepaid Small Flat Rate Box
  • Priority Mail Forever Prepaid Medium Flat Rate Box – 1
  • Priority Mail Forever Prepaid Medium Flat Rate Box – 2
  • Priority Mail Forever Prepaid Large Flat Rate Box

How Much Do USPS Boxes Cost?

Most USPS boxes are free, including Regional Rate boxes and Flat Rate boxes. This is also true of all packaging for all USPS Priority Mail and Priority Mail Express services. To clarify, Flat Rate and Regional Rate fall under the umbrella of Priority Mail services, so that’s why they come with free USPS boxes.

Free USPS boxes can be ordered on the USPS site in packs of 10 or 25. Delivery is free.

You will have to purchase Forever Prepaid Flat Rate boxes, however. They are available in three sizes and can be ordered on the USPS site. The minimum order quantity is 5. Here are prices for each USPS Forever Prepaid Flat Rate box size:

  • Small: $8.45
  • Medium: $15.50
  • Large: $12.90

For more tips on free boxes for shipping, check out this guide to free packaging.

How to Get The Cheapest USPS Shipping

Shipping with USPS brings a lot of considerations – which USPS boxes to use, which service to pick, and the total cost, after all, is said and done.

You can skip over all this research with the Easyship Free Shipping Rate Calculator. All you need to do is enter your shipment weight and delivery destination to see real-time accurate rates for all the cheapest shipping services available, including USPS.

Here are the rate quotes for shipping a 2-pound package from New York, NY to Denver, CO.

The cheapest option for our needs is USPS - Ground Advantage at $7.78. How much easier is this than scouring the USPS site for rates, getting a quote, then doing the same at FedEx, DHL, UPS, etc?

Our rate calculator is always free to use. Plus, it shows you the savings you’ll get by using Easyship for USPS shipping with the corresponding USPS boxes. As seen above, Easyship can save you $16.45 off retail prices from USPS.

As you research boxes and prices, it’s important to remember that you can usually skip this step by using Easyship to aggregate all the cheapest rates. Then, all you need to do is order free USPS boxes online and it's a wrap.

USPS Boxes With Easyship Shipping

Most USPS boxes are free. If you’re using Flat Rate from USPS, you’ll need to order Flat Rate boxes from the USPS site. Regional Rate boxes can be used for Regional Rate shipping from USPS, but you can also use your own packaging (though it’ll cost a bit more). Use USPS Forever Prepaid Flat Rate Boxes to lock in today's cheap Flat Rate prices.

Easyship can help you save up to 91% of all USPS shipping rates, regardless of what boxes you use. Our partnership with USPS means you get our pre-negotiated discounted rates on every order you place with Easyship. When you do so, you’ll be able to use our time-saving shipping automation to boost online sales and streamline your fulfillment processes.

Ready to try Easyship? Create a free account today and give our all-in-one shipping software a look-see.

USPS Shipping Boxes FAQ

What do I do with unused USPS boxes?

Unused USPS boxes can be returned to the nearest Post Office for re-use.

Can I order USPS boxes online?

Yes, and delivery is free. You can also get some USPS boxes from your local Post Office, but there's no guarantee what you need will be in stock.

How do I track a free USPS box?

All USPS tracking is done by following the tracking link on your shipment receipt on