If you are unsure, try a USPS Shipping Calculator. In addition, the flat rate price guarantees that you’re not charged with increased costs for the size and weight of your package. USPS flat rate shipping large boxes offer a practical and straightforward way to ship large packages quickly. If you’re sending a package, you’ll be happy to hear that flat-rate shipping offers free pickup service at your home or office. As a result, you can expect delivery in one to three business days. Note that flat rate boxes all ship using USPS priority mail service, offering quick delivery times. These dimensions give you ample freedom of choice when it comes to the items you want to ship.Ĭompared to the large box, the USPS Flat Rate Boxes Small are tiny and can only fit something like a couple of DVDs or a thin book. In terms of weight, anything up to 70 lbs is fair game. That’s quite roomy for a shipping box, so you could easily send or receive an entire desktop PC or a bunch of books. On the inside, the USPS large box measures 12′′ x 12′′ x 5 1/2′′. First, we’ll tell you about the 'large box,' the biggest one USPS has to offer. USPS Flat Rate Boxes come in various sizes, from tiny to very spacious.

With USPS flat rate shipping, you get fixed postage rates, as long as your package fits inside one of the company’s standard boxes.

Usps flat rate box sizes and pricing