Dimensional Weight? What's that?

It's a little known rule that the Post Office, UPS, FedEx and other carriers use when determining the shipping charges for a package. And not knowing when dimensional (DIM) weight applies can result in a surprising increase in what you pay.

Here's an illustration to show you why the carriers use DIM weight....let's say you're shipping a wicker chair from California to Florida (an actual occurence in a PostalAnnex+ transaction once).
While wicker is very light, a chair is very large in dimensions. Thus, a 48" tall box that is 36" x 36" at its base may only weigh 20 pounds.

The carriers are essentially saying, "That box will take up a lot of room in my truck. But because I charge by weight, I'm not getting very much for your 20-pound chair. And I could've put another package or two in the space your lightweight chair took in my truck, so I'm going to charge you more for your big, but light, box."

Imagine a more extreme example of a refrigerator-sized box of feathers. If the carriers charged purely by weight, you'd have a low shipping bill. And the carrier loses because he could have put more boxes from other people in the space your refrigerator-sized box took. That adjustment of the actual weight because the of the size is dimensional weight.

How is DIM weight calculated?

For UPS and FedEx, if the volume (space) of a shipping box is greater than 3 cubic feet, dimensional weight may apply.

1. To figure the volume, multiply the length x width x height.
2. To calculated the dimensional weight, divide the above result by 194. The denominator of 194 is an industry standard number.
3. If the dimensional weight exceeds the actual weight, the customer will be billed the dimensional weight. Otherwise, the actual weight is what is billed.

Here's an example:

1. Let's take a box 30" x 15" x 15" which is 6.750 cubic inches....divided by 194 = 34.79 lbs DIM weight.
2. Let's say that box has an actual weight (including the box) of 18 pounds.
3. The customer will pay for 35 pounds because dimensional weight exceeds actual weight. That's almost double the actual weight!

Other factoids:

1. DIM weight is calculated differently for air shipments. The above information is for packages shipping via ground service only.
2. The Post Office has different DIM rules than UPS and FedEx.
3. International shipments have different DIM rules as well.

What can you do to avoid DIM weight?

1. Make sure your shipping carton is sized right for your shipment. You should have at least 2" clear space between any interior edge of the box and the object(s) being shipped. More than 2" might mean your box is too large, and you might be paying more shipping charges than you need .
2. Remember, the dimensions printed on any shipping carton are the interior dimensions. The carriers measure exterior dimensions. So be sure to measure exterior dimensions when calculating shipping rates.
3. Carriers round up dimensions to the next whole inch. A side that measures 12-1/2" is considered to be 13 " by the carriers.
4. Carriers round up ounces to the next whole pound. So one more sheet of bubble wrap that pushes a 15lb package to 15lbs, 1 oz, is now a 16-lb packages.

In summary, pay attention to the size of your shipping carton. You need adequate protection for your contents, but not too much that your shipping charges increase as a result of unneeded space.

Don't want to fret over packaging your shipment so that you avoid DIM weight while packaging correctly for the rules of insurability? Let any one of our PostalAnnex+ packaging experts help you with your shipment. There may be a PostalAnnex+ location in your neighborhood.

If you're looking to become a small business owner yourself in your community, consider PostalAnnex+ in your future.


Steve & Vicki Collo, Franchisees since 1993, made their PostalAnnex+ business a family business.

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