At the beginning of 2015, UPS and FedEx shifted their billable weight rules to account for the dimensional weight of all ground shipments. Here’s the original statement from FedEx on the matter.
If you’re wondering, “How do I calculate dim weight?” you’re not alone. Not only can dim weight be complicated to measure, but it can also be more expensive. Here’s what you need to know about dim weight in light of the recent changes.
What is dim weight?
Dim weight – short for dimensional weight – measures a package’s size instead of its actual weight on a scale. It’s actually designed to reflect package density. Charging by dim weight is a method to avoid lightweight packages while incentivizing merchants and fulfillment centers to use the most compact and smallest possible packages to ship items.
UPS and FedEx will measure both the actual weight and the dimensional weight, and ultimately charge the greater value.
While you can measure the actual weight of a package on a scale, there’s no scale that can measure dim weight. Calculating dim weight calls for a little bit of math.
How to determine dim weight
There are two steps to calculating dim weight. The first starts with measuring the length, width, and height of the package in inches. Multiply those together to get the cubic size of your package.
The next step is to divide the cubic size by a standard number to determine the dimensional weight in pounds. For domestic shipments (including Canada) you’ll divide the cubic size of your package by 166, but for international shipments you’ll divide it by 139.
Round that number to the closest whole pound, and you’ve got your dim weight.
Here’s a quick example of a basic package size of 8 x 8 x 8.
Cubic size: 512 cubic inches
Dim weight, domestic and Canada: 3.08, round down to 3 lbs
Cubic size divided by 166
Dim weight, international: 3.68, round up to 4 lbs
Cubic size divided by 139
If you’d like a more detailed walkthrough, the UPS has a great overview of how to determine billable weight on their website.
What does it mean for me?
Following the rules to measure billable weight can be a headache. You can avoid high dim weight charges by shipping items in the smallest possible box, regardless of weight. It’s a balancing act between which number will be larger: actual weight, or dim weight.