Dim Weight Calculator

In Partnership with Pregis

Adapting to Dimensional Weight Restrictions

Over 5 years ago dimensional weight restrictions permanently changed the world of parcel. Before that, shipping rates were purely calculated based on weight - the heavier the box, the more it cost to ship.

Companies had to redesign their packaging solutions to accommodate a new pricing structure that considered both the package weight and volume. If this was not done properly, shippers faced high fees and major price increases. This model still exists today and likely isn’t going away.

According to FedEx, “Dim weight is the amount of space a package occupies in relation to its actual weight. For each shipment, you are charged based on the dimensional weight or actual weight of the package—whichever is greater.”

How Did Dim Weight Restrictions
Come to Be

The purpose of dimensional weight restrictions is to reduce emissions due to poorly packed boxes. Empty space in a package means higher costs and negative impacts on the environment. Extra void fill is also needed when there is a lot of empty space in a box. Not only is this wasteful for the shipper, but it is also a waste of natural resources.

Shipping companies essentially forced shippers to make their packages smaller to help the environment, and their bottom lines. Trucks have weight restrictions that parcel companies have to follow; if they don’t properly charge their customers, they could be at a deficit.

Finding a Proper Dim Weight Strategy

Package Materials

The container used for packaging makes a difference; both packaging mailers and corrugated boxes can be used when appropriate


Properly measuring your package is critical for accurately assessing costs

Void Fill

Dunnage options are endless – find the right balance between protecting your products and minimizing empty space


Every carrier has it’s own set of Dim weight rules and restrictions. It’s important to understand these costs upfront.


Package weight still matters. Dim weight considers both the volume and the weight of the package.

Tips for Calculating Dim Weight

Dimensional weight reflects package density (amount of space a package occupies). For each dimension, measure at the longest point, rounding each measurement to the nearest whole number (for example, 1.00 to 1.49 will be considered 1 and 1.50 to 1.99 will be considered 2). The dim divisor for a customer who has daily rates (this would be a customer who has a UPS account and set pricing) is 139 and the divisor for retail rates is 166.

To get the dimensional weight, a customer would take the L x W x H divided by the divisor (139). If a customer ships a 24x24x12 box, for example, the dimensional weight is 50 pounds. The customer would need to put something in that box that is over 50 pounds to be charged actual weight versus dimensional weight.

We recommend that our customers pack items in a box/envelope as tightly as possible with as little "air space" as possible.

The Impact of E-Commerce

As e-commerce has exploded, parcel companies have been expanding to accommodate the sheer volume of packages circulating the globe every day. E-commerce has continued to explode at unprecedented levels, with an endless variety of products being ordered by consumers and businesses. Parcel companies had to create more solutions for this problem that didn’t depend on the number of trucks - such as dimensional weight restrictions. All of the major parcel companies have their own shipping factor and calculations for dim weight, but the bottom line is e-commerce companies in particular need to be focused on eliminating the empty space in their boxes.

The Impact of Free Shipping

Fast and free shipping has become expected in the e-commerce shopping experience. This means that companies have to seek the most cost effective shipping solutions in order to preserve their bottom lines. Creating a package that is most efficient for dimensional weight means having a plan to balance the costs of shipping with the pressure of low/no costs to the customer. At Morrisette, we help our customers explore the best packaging options to achieve this goal.

More Considerations

  • Anyone who relies on shipping goods to customers needs to pay attention to the current dimensional weight factors for their chosen parcel company. These rates can change at any time. If the weight factor goes down, this causes an increase in the shipping cost. This impact can be dramatic for companies of all sizes.

  • Parcel companies measure the outside dimensions of the box, but box companies often market the inside dimensions. This can be a difference of a quarter to half an inch. If you apply this to every package, you can be making wrong projections about your shipping fees.

  • UPS will always bill a package based on the billable weight (actual weight or dimensional weight, whichever is greater of the two). Actual weight will be the weight rounded up to the next whole pound. Round any fraction of a pound to the next whole pound.

Find Out If You Could Save Money With A More Effective Dim Weight Strategy