USPS Priority Mail Flat Rate boxes are an easy-to-use,cost-effective shipping option. You can easily ship like the experts; just know the USPS Flat Rate box sizes, prices, and how it works before you buy.
How Does USPS Flat Rate Shipping Work?
The USPS Priority Mail Flat Rate service will ship your package anywhere in the U.S. in 1-3 business days for a flat fee. To ship with this service, follow these easy steps:
- Order free Flat Rate boxes from the USPS. You have to use the branded Flat Rate boxes to get the Flat Rate shipping price, and you can order them online or pick them up at your local Post Office.
- Sign up for a free Shippo account to access the best rates on USPS Flat Rate shipping and print your labels from the comfort of your office or home.
- Bonus! Determine if a USPS Flat Rate box is the cheapest option for the items you’re looking to ship, since it’s not always the most affordable choice.
What are the 2023 USPS Flat Rate Box Sizes and Prices?
As you’ll see below, Shippo offers discounted shipping rates when compared to what you’d find at your local Post Office. No volume or coding requirements. On top of this, Shippo merchants get access to special pricing on Priority Mail Flate Rate services during peak season. Sign up for a free Shippo account, to see live discounted rates and print USPS labels for Flat Rate Boxes.
2023 USPS Priority Mail Flat RateShippo vs. Retail Rates | |||||
| Products | Dimensions | Shippo Rate | Retail Rate | Savings Using Shippo vs. Retail | % Savings with Shippo |
| Flat Rate Envelope | 12 ½” x 9 ½” | $7.60 | $9.65 | $2.05 | 21.24% |
| Legal Flat Rate Envelope | 15” x 9 ½” | $7.90 | $9.95 | $2.05 | 20.60% |
| Padded Flat Rate Envelope | 12 ½” x 9 ½” | $8.30 | $10.40 | $2.10 | 20.19% |
| Small Flat Rate Box | Outside: 8 11/16” x 5 7/16” x 1 ¾” Inside: | $8.10 | $10.20 | $2.10 | 20.59% |
| Medium Flat Rate Box – 1 (Top-Loading) | Outside: 11 ¼” x 8 ¾” x 6” Inside: | $14.00 | $17.10 | $3.10 | 18.13% |
| Medium Flat Rate Box – 2 (Side-Loading) | Outside: 14” x 12” x 3 ½” Inside: | $14.00 | $17.10 | $3.10 | 18.13% |
| Large Flat Rate Boxes | Outside: 12 ¼” x 12 ¼” x 6” Inside: | $18.95 | $22.80 | $3.85 | 16.89% |
Is Priority Mail the Same as Flat Rate?
USPS Priority Mail is one of the most popular service levels the Postal Service offers, and for good reason. It’s cost-effective and encompasses three widely-used shipping options: Priority Mail Flat Rate (which we discussed above), Priority Mail weight-based, and Priority Mail Cubic.
To ship via Flat Rate, you need to use the Flat Rate branded boxes. To use Cubic and weight-based options, you must use your own packaging or USPS Priority Mail boxes.
Which is Cheaper: Flat Rate or Priority Mail?
Generally speaking, the USPS Flat Rate boxes are a great option for heavy items that are traveling long distances.We ran the numbers to find out exactly when you should use a Flat Rate box and when you should use your own packaging and ship via USPS Priority Mail weight-based or Cubic instead.
When to Use USPS Flat Rate Envelopes
- USPS Flat Rate Envelopes are almost ALWAYS the cheapest option.
- However, use your own envelope for packages weighing exactly 1 lb. and traveling locally.
- And if your package weighs less than 1 lb., use your own envelope and ship via USPS First-Class Package Service.
Use your own envelope (NOT a Flat Rate envelope) for the following scenarios:
Flat Rate Envelope (12 1/2″ x 9 1/2″) – $7.60 | ||
| Qualifications for Using Own Packaging | Cost to Ship | Savings |
| Weighs 0.5-1 lb. and traveling less than 50 miles (Zone 1) | $7.09 | $0.51 |
Legal Flat Rate Envelope (15″ x 9 1/2″) – $7.90 | ||
| Qualifications for Using Own Packaging | Cost to Ship | Savings |
| Weighs 0.5-1 lb. and traveling 500 miles (Zone 4) | $7.58 | $0.32 |
Padded Flat Rate Envelope (12 1/2″ x 9 1/2″) – $8.30 | ||
| Qualifications for Using Own Packaging | Cost to Ship | Savings |
| Weighs 0.5-1 lb. and traveling 500 miles (Zone 4) | 7.58 | $0.72 |
| Weighs 2 lbs. and traveling less than 50 miles (Zone 1) | $7.11 | $1.19 |
When to Use USPS Flat Rate Boxes
- For 1 – 20 lb. packages, choose Flat Rate for long distances and your own box for short distances.
- For <1 lb. packages, use your own box and ship via USPS First-Class Package Service.
- For >20 lb. packages, use a Flat Rate box.
Use your own box (NOT a Flat Rate box) for the following scenarios:
Sm. Flat Rate Box (8 5/8″ x 5 3/8″ x 1 5/8″) – $8.10 | ||
| Qualifications for Using Own Packaging | Cost to Ship | Savings |
| Weighs 2 lbs. and traveling 500 miles (Zone 4) | $7.60 | $0.50 |
Med. Flat Rate Box (11 1/4″ x 8 3/4″ x 6″) – $14.00 | ||
| Qualifications for Using Own Packaging | Cost to Ship | Savings |
| Weighs 1 lbs. and traveling 2,000 miles (Zone 8) | $9.43 | $4.57 |
| Weighs 10 lbs. and traveling 1030 miles (Zone 6) | $12.38 | $1.62 |
Lg. Flat Rate Box (12 1/4″ x 12 1/4″ x 6″) – $18.95 | ||
| Qualifications for Using Own Packaging | Cost to Ship | Savings |
| Weighs 0.5-1 lb. and traveling to (Zone 8) | $9.43 | $9.52 |
| Weighs 3 lbs. and traveling to (Zone 8) | $15.48 | $3.47 |
| Weighs 4 lbs. and traveling to (Zone 7) | $18.57 | $0.38 |
Keep in mind that the maximum weight is 70 pounds. And, when sealing a Flat Rate envelope or box, the container flaps must be able to close within the normal folds.
Is Priority Mail (Weight-based) or Flat Rate Faster?
Technically speaking, they are all part of the Priority Mail mail stream, so they all ship within 1-3 business days.
Are There Any Other Restrictions?
There are specific regulations and standards for mailing restricted, prohibited, and hazardous materials, including cigarettes and smokeless tobacco. You also can’t ship airbags, ammunition, explosives, or gasoline. For more details, visit the USPS Shipping Restrictions page.
How Do I Get a USPS Priority Mail Flat Rate Label?
Setting up a free Shippo account takes just a few minutes, and then you can print the label from your office or warehouse. (Feel free to check out our USPS shipping calculator to get a clearer picture of how you can save on USPS shipping rates by using Shippo.) Affix the label to the USPS Priority Mail Flat Rate box. Then, put it in your mailbox or schedule a pick-up with your local mail carrier in the Shippo dashboard.
Make sure the label you’re using matches the packaging. For example, if you use a Priority Mail Express Flat Rate box, you need to use a Priority Mail Express Flat Rate label.
If you liked this post, you may also be interested in a video that our co-founder Laura Behrens Wu did with the co-founder of packaging solution company Lumi on shipping with the USPS.
Shippo is a multi-carrier API and web app that helps retailers, marketplaces, and platforms connect to a global network of carriers. Businesses use Shippo to get real-time rates, print labels, automate international paperwork, track packages and facilitate returns. Shippo provides the tools to help businesses succeed through e-commerce shipping.
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Michelle McNamara is a Senior Marketing Manager at Shippo
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2023 USPS Flat Rate Box Sizes, Prices, and How it Works? ›
To use the service, you choose a box or envelope, which has a flat fee assigned to it. It doesn't matter how much the box or envelope weighs; if it fits, it ships. Though there is an upper limit of 70 pounds. Also, the box or envelope must close naturally so that you can secure it.
How does flat rate boxes work at USPS? ›To use the service, you choose a box or envelope, which has a flat fee assigned to it. It doesn't matter how much the box or envelope weighs; if it fits, it ships. Though there is an upper limit of 70 pounds. Also, the box or envelope must close naturally so that you can secure it.
Is it cheaper to use a flat rate box or your own box? ›For shipments traveling shorter distances, Zones 1-4, and weighing less than 20 lbs, using your own packaging for weight-based rates may be a better value. Across all zones, though, shipments weighing over 25 lbs will ship for less in a Flat Rate Large Box.
What are the post office changes for 2023? ›WASHINGTON, DC — Today, the United States Postal Service filed notice with the Postal Regulatory Commission (PRC) of mailing services price changes to take effect July 9, 2023. The new rates include a three-cent increase in the price of a First-Class Mail Forever stamp from 63 cents to 66 cents.
How much does each flat rate box cost? ›| Free Supplies8 | Shipping Price |
|---|---|
| Legal Flat Rate Envelope | $8.35 Commercial Pricing $9.95 at Post Office & Online |
| Small Flat Rate Box | $8.55 Commercial Pricing $10.20 at Post Office & Online |
| Medium Flat Rate Box — 1 (top-loading) | $14.75 Commercial Pricing $17.10 at Post Office & Online |
How does flat rate shipping work? To use USPS flat rate shipping, you need to get a USPS flat rate box from your local USPS office (small, medium, or large size), add no more than 70 pounds of contents that fit inside the box, label an address, and ship the box at a USPS office using Priority Mail.
How much is a medium flat rate box 2023? ›The cheapest way to ship flat rate boxes depends on the exact size of the box, and for some providers, the speed and distance it will travel. For single boxes, USPS is often the cheapest option. For larger boxes or shipments of multiple boxes, consolidated freight is one of the most cost-effective shipping methods.
What is the cheapest flat rate box at the Post Office? ›| Package | Price |
|---|---|
| Priority Mail Small Flat-Rate Box | $4.95 |
| Priority Mail Medium Flat-Rate Box (FRB1) | $10.35 |
| Priority Mail Medium Flat-Rate Box (FRB2) | $10.35 |
| Priority Mail Large Flat-Rate Box | $13.95 |
You may already know that anyone shipping a package through USPS can walk into a post office, pick up a free Priority Mail® envelope or box, and pay a flat rate to ship it. But are post office shipping boxes free for businesses as well? The answer is yes, you can pick up free boxes at the post office.
What is the difference between Priority Mail and flat rate box? ›
The main difference between USPS Priority Mail and USPS Flat Rate is the way the shipping cost is calculated. USPS Priority mail uses the dimensional weight and shipping distance to calculate the shipping cost. On the other hand, USPS Flat Rate uses only the package size to calculate the shipping cost.
Are USPS flat rate boxes free at the Post Office? ›The answer is yes, you can pick up free boxes at the post office. What's more, you can order USPS boxes free online.
Can I use a USPS flat rate box but pay by weight? ›As long as your Priority Mail Flat Rate box or envelope isn't sealed with the self-adhesive strip it comes with, you can technically alter the packaging to qualify for weight-based Priority Mail rates... but this almost never works out, and USPS will likely charge you for that specific flat rate service after they ...
Can you just take flat rate boxes from USPS? ›Flat rate boxes can be picked up at your local Post Office™ or ordered online—both for $0! If you have the boxes readily available your employees and colleagues are more likely to use them. Convenience is key!