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How USPS Flat Rate Works

USPS Priority Mail Flat Rate boxes are an excellent option for cost-effective and efficient shipping. This guide provides detailed information on the various USPS Flat Rate box sizes, prices, and how to use this service to your advantage.

How Does USPS Flat Rate Shipping Work?

USPS Priority Mail Flat Rate service allows you to ship packages anywhere in the U.S. for a flat fee, regardless of the weight (up to 70 lbs) or destination. Packages are delivered within 1-3 business days. Here's how to use the service:

  1. Choose the Right Box : Select a Flat Rate box that fits your items.
  2. Pack Your Items : Ensure your items are securely packed and the box flaps can close within the normal folds.
  3. Print a Shipping Label : Use the USPS website.
  4. Attach the Label: Affix the label to the Flat Rate box.
  5. Send Your Package: Drop off the package at your local Post Office or schedule a pickup

2024 USPS Flat Rate Box Sizes and Prices

Current USPS Priority Mail Flat Rate sizes and prices:

Product Dimensions Retail Rate
Flat Rate Envelope 12 ½” x 9 ½” $9.85
Legal Flat Rate Envelope 15” x 9 ½” $10.15
Padded Flat Rate Envelope 12 ½” x 9 ½” $10.60
Small Flat Rate Box 8 11/16” x 5 7/16” x 1 ¾” $10.40
Medium Flat Rate Box 11 ¼” x 8 ¾” x 6” $18.40
Large Flat Rate Box 12 ¼” x 12 ¼” x 6” $24.75
APO/FPO/DPO Large Box 12 ¼” x 12 ¼” x 6” $20.15

Choosing the Right Flat Rate Option

  • Flat Rate Envelope : Ideal for documents and small items up to 70 lbs.
  • Legal Flat Rate Envelope : Best for slightly larger documents.
  • Padded Flat Rate Envelope : Perfect for items that need extra protection.
  • Small Flat Rate Box : Suitable for small, dense items.
  • Medium Flat Rate Box : Good for medium-sized items.
  • Large Flat Rate Box : Best for large, heavy items.
  • APO/FPO/DPO Large Box : Designed for military addresses.

Is Priority Mail the Same as Flat Rate?

USPS Priority Mail includes three options:

  1. Priority Mail Flat Rate : Fixed price regardless of weight or distance.
  2. Priority Mail Weight-Based : Price based on the weight and distance.
  3. Priority Mail Cubic : Price based on package size and distance.

To use Flat Rate, you must use USPS-branded Flat Rate boxes. For weight-based and cubic options, you can use your packaging or USPS Priority Mail boxes.

When to Use USPS Flat Rate vs. Priority Mail

Flat Rate Envelopes

  • Almost always the cheapest option for documents and small items.
  • Use your own envelope if the package weighs exactly 1 lb and is traveling locally.
  • For packages under 1 lb, use your own envelope and ship via USPS First-Class Package Service.

Flat Rate Boxes

  • For 1-20 lb packages, use Flat Rate for long distances and your own box for short distances.
  • For packages over 20 lbs, use a Flat Rate box.

Are There Any Restrictions?

Yes, USPS has specific regulations for restricted, prohibited, and hazardous materials, including:

  • Cigarettes and smokeless tobacco
  • Airbags, ammunition, explosives, and gasoline

For more details, visit the USPS Shipping Restrictions page.

How to Get a USPS Priority Mail Flat Rate Label

Visit the USPS website to create and print a label. Affix it to the Flat Rate box and drop it off at your local Post Office or schedule a pickup.

Make sure the label matches the packaging type. For instance, use a Priority Mail Express Flat Rate label for a Priority Mail Express Flat Rate box.

USPS Flat Rate shipping offers a convenient, cost-effective solution for shipping packages of various sizes and weights across the U.S. By understanding the different Flat Rate options and choosing the right one for your needs, you can ensure your packages are delivered quickly and affordably.

How to ship with USPS without Flat Rate

Set up a free Qwintry Global account quickly and easily. Print a shipping label, affix it to the box, and drop it off at your local Post Office or schedule a pickup. Save up to 40% on USPS shipping services with Qwintry Global. Use the Qwintry Global Shipping Calculator to check rates.

Sign up now to streamline your shipping process and access discounts!


Posted 2 months ago