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UPS Box Dimensions: UPS’s Own Boxes, Store Sizes and Simple Rate
By UPS box dimensions depend on which box you mean. UPS’s own Express Boxes are 13 x 11 x 2, 15 x 11 x 3 and 18 x 13 x 3 inches, and UPS lists them for its air and international express services. The UPS Store lists 21 standard sizes, from 6 x 6 x 6 to 30 x 24 x 6. And UPS Simple Rate takes any box up to 1,728 cubic inches, priced in five size bands. If you are designing a mailer box to ship by UPS Simple Rate, those bands set its price tier.
UPS Box Dimensions for UPS’s Own Boxes
UPS’s WorldShip help lists its standard package types with their sizes, in inches:
| UPS package | Dimensions | Weight limit listed | Listed for |
|---|---|---|---|
| Express Box Small | 13 x 11 x 2 | Not listed | Next Day Air Early, Next Day Air, Next Day Air Saver, 2nd Day Air, Worldwide Express, Worldwide Express Plus |
| Express Box Medium | 15 x 11 x 3 | Not listed | Same as Small |
| Express Box Large | 18 x 13 x 3 | Up to 30 pounds | Same as Small |
| UPS Pak | 16 x 13 x 1 | Not listed | Next Day Air, 2nd Day Air, Worldwide Express, Worldwide Expedited |
| UPS Tube | 38 x 6 x 6 | Not listed | Next Day Air Early, Next Day Air, Next Day Air Saver, Worldwide Express, Worldwide Express Plus |
| 10 KG Box | 17 x 13 x 11 | Up to 10 kg (22 pounds) | Prepaid Worldwide Express and Worldwide Express Plus from the US and Puerto Rico |
| 25 KG Box | 19 x 17 x 14 | Up to 25 kg (55 pounds) | Same as 10 KG Box |
Two things stand out: UPS Ground is not among the services listed for any of these boxes, and the Medium Express Box appears on the pages benchmarked for this post at 16 x 11 x 3 and 17 x 12 x 3; UPS’s own help says 15 x 11 x 3. It is worth measuring the box you actually have before you plan a product around it.
The UPS Store’s Standard Sizes, and Which Fit Simple Rate
The UPS Store’s packing supplies page lists 21 standard box sizes, and tells you to contact your local store for specific sizes, prices and availability. The source page for this post lists them as UPS box dimensions; they are the store’s stock. Here they are, in inches, with the cubic size and the Simple Rate band each nominal size falls in:
| The UPS Store size | Cubic inches | Simple Rate band |
|---|---|---|
| 6 x 6 x 6 | 216 | Small |
| 8 x 8 x 8 | 512 | Medium |
| 10 x 10 x 10 | 1,000 | Large |
| 12 x 12 x 6 | 864 | Large |
| 16 x 16 x 4 | 1,024 | Large |
| 17 x 11 x 8 | 1,496 | Extra Large |
| 12 x 12 x 12 | 1,728 | Extra Large, exactly at the limit |
| 6 x 6 x 48 | 1,728 | Extra Large, exactly at the limit |
| 15 x 12 x 10 | 1,800 | Over the limit by 72 |
| 14 x 14 x 14 | 2,744 | Over |
| 16 x 16 x 16 | 4,096 | Over |
| 18 x 18 x 18 | 5,832 | Over |
| 20 x 12 x 12 | 2,880 | Over |
| 20 x 20 x 12 | 4,800 | Over |
| 20 x 20 x 20 | 8,000 | Over |
| 24 x 18 x 6 | 2,592 | Over |
| 24 x 18 x 18 | 7,776 | Over |
| 24 x 24 x 16 | 9,216 | Over |
| 24 x 24 x 24 | 13,824 | Over |
| 30 x 24 x 6 | 4,320 | Over |
| 15 x 15 x 48 | 10,800 | Over |
Eight of the 21 nominal sizes fall inside Simple Rate, and two of them sit exactly on the 1,728 cubic inch limit, which matters for the rounding rule below.
How Simple Rate’s Size Bands Work
UPS’s Simple Rate page, as listed in the US on 1 October 2026, sets five bands by cubic inches:
- Extra Small: 1 to 100
- Small: 101 to 250
- Medium: 251 to 650
- Large: 651 to 1,050
- Extra Large: 1,051 to 1,728
You can use “any box or mailer” up to 1,728 cubic inches; above that, or over 50 pounds, the page says the package goes back to standard rates based on dimensional weight and zone. Simple Rate is for shipments within the 50 US states only.
The Round Up Rule at a Band Edge
UPS’s size and weight guide tells you to “round up to the nearest whole number” when you measure, so 1.01 to 1.99 becomes 2, and says you will need those measurements when you create your shipment. Rounding can move a box into the next band.
- A box 8 x 6 x 2 inches is 96 cubic inches: Extra Small.
- The same box at 8 x 6 x 2.25 is entered as 8 x 6 x 3: 144 cubic inches, Small.
- A 12 x 12 x 12 box is exactly 1,728. If its outside measures even a fraction over 12 on one side, it is entered as 13 on that side: 1,872 cubic inches, over the Simple Rate limit.
Measure the outside of the packed box, not the size printed on its side or in the supplier’s listing.
Sizing a Custom UPS Box
- Start from the outside dimensions. Design the outside to whole inches, then check a sample with a tape measure.
- Aim under a band edge, not on it. Check the cubic size of the outside dimensions against the five bands above.
- Check the limits for larger boxes. UPS’s size and weight limits are covered in our guide to shipping large items, and dimensional weight in our guide to how much a cardboard box weighs.
- Match the board to the load. Give us the filled weight and how it travels, and we confirm the board at quote.
Our minimum order is 100 boxes. Custom Boxes Deals makes boxes to the size you specify, including corrugated shipping boxes and mailer boxes.
Frequently Asked Questions
What size is a UPS medium box?
UPS’s WorldShip help lists the Express Box Medium at 15 x 11 x 3 inches. Some websites give 16 x 11 x 3 or 17 x 12 x 3.
Can I use a UPS Express Box for UPS Ground?
UPS’s WorldShip help lists the Express Boxes for its Next Day Air, 2nd Day Air and Worldwide Express services. UPS Ground is not on that list.
Does UPS have a flat rate box?
Not a fixed one. UPS Simple Rate prices your own box or mailer by its cubic size, up to 1,728 cubic inches and 50 pounds. UPS also sells branded boxes for it.
What is the biggest box for UPS Simple Rate?
1,728 cubic inches, such as 12 x 12 x 12, measured with each side rounded up to the next whole inch.
Anthony Kim
Hello, I'm Anthony Kim, a seasoned packaging consultant and designer. With a professional journey spanning over four years, I've evolved from a budding designer to a recognized expert in the field. Currently holding the position of Packaging Consultant, I've honed my skills in creating not just visually stunning packaging but also solutions that align with strategic business goals.
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