UPDATE: The principles and formulas for dimensional weight (DIM weight) rules below are a great resource for ecommerce retailers. For updated examples of DIM weight formulas, including 2020 DIM weight factors for FedEx, DHL and UPS, visit: Online Sellers Guide to Dimensional Weight.
FedEx and UPS changed their dimensional weight rules starting 2015. UPS dimensional weight rules from 2015 remain in place. Fedex recently announced new dimensional weight rules for 2017. For an up-to-date overview of how DIM rules apply, please visit our most recent post: New FedEx & UPS Dimensional Weight Rules.
Have you seen those USPS commercials for their Flat Rate Boxes; you know, the ones where people are so amazed at how easy shipping is?
Well, if you’re an online merchant, you know that your stuff doesn’t always fit neatly into a flat rate box, which means that shipping isn’t always easy. Sometimes, it’s flat out complicated, especially when dimensional weight comes into play.
As an eCommerce fulfillment center, we’re often asked how to calculate dimensional weight. We’ll get into that shortly, but let’s start with a quick overview of what it actually is.
What is Dimensional Weight?
Dimensional weight, also known as “dim” weight, is a tactic used by shipping and freight companies to basically ensure they don’t lose money on lightweight packages. Dim weight has long been used for air freight, and about 5 years ago, the big shipping carriers like FedEx and UPS also started applying dimensional weight to packages shipped via ground service.
Dimensional weight works by calculating the cubic size of a package by multiplying its length, width and height. Once the dimensional weight is calculated, it is then compared to the actual weight of the package in some circumstances, and the larger of the two is used to determine the package’s actual billable weight.
When it comes to eCommerce order fulfillment, online merchants are often concerned about when dim weight will actually be triggered, and how they can anticipate those charges. So let’s talk about how to calculate dimensional weight, and when it’s applied.
How Do You Calculate Dimensional Weight?
To determine the dim weight of a package, you must first measure the length, width and height of the package in inches using the longest point on each side, taking into account any bulges or misshaped sides.
You then multiply those dimensions to get the cubic size of the package. For example, let’s say your package is 30” x 12” x 12”. In this case, you multiply these 3 dimensions and determine that the package is 4,320 cubic inches.
When calculating dimensional weight, it’s important to keep in mind that most shipping carriers will have you round to the nearest whole number. For instance, if the width of your package is 12.50 inches or above, you’d round up to 13”. If it’s 12.49” or below, you’d round down to 12”.
To determine the dimensional weight of a package, the major carriers, UPS and FedEx, currently use the same calculation, which is the cubic size of a package divided by 166 for domestic shipments, and 139 for international shipments. (Note: in 2020 FedEx uses a DIM weight factor of 139. UPS uses a DIM weight factor based on rate type. For Daily Rates the UPS weight factor is 139, for Retail Rates the UPS weight factor is 166.) These calculations are shown in more detail below:
What is Dimensional Weight Pricing?
Dimensional weight pricing is defined as the price that is paid for shipping based on the cubic size of the package that is being shipped.
In many cases, the package size and overall dimensional weight are used as factors in determining the package’s billable weight, which is the final weight used to determine the actual pricing of shipping the package. But, depending on your carrier, dim weight isn’t always used to determine billable weight, and this is where it can get somewhat complicated.
Here’s how it works. If your package is being delivered via air service, the billable weight will always be subject to dimensional weight. If it’s being shipped via ground service, however, generally it is only subject to dim weight if the cubic size of the package is 3 cubic feet or larger (5,184 cubic inches). If the cubic size is less than 3 cubic feet, dimensional weight will not apply, and the actual weight of the package will always be used.
I know, a little confusing, right? To help clear all this up, let’s take a look at a few examples below.
Example 1
Ship Method / Destination: Ground / Domestic
Actual Weight: 21 pounds
Length: 30 inches
Width: 12 inches
Height: 12 inches
Cubic Size Calculation: 30 x 12 x 12 = 4,320 cubic inches
Dimensional Weight Calculation: 4,320/166 = 26 pounds
In this first example, because it is a domestic shipment, we multiply the total cubic size in inches by 166. In doing so, we find out that the dimensional weight is 26 pounds, which is greater than the actual weight.
However, because the package is being shipped via ground service and is less than 5,184 cubic inches, the dimensional weight is not applied. So in this case, the actual weight of 21 lbs. becomes the billable weight.
Example 2
Ship Method / Destination: Ground / Domestic
Actual Weight: 32 pounds
Length: 30 inches
Width: 15 inches
Height: 15 inches
Cubic Size Calculation: 30 x 15 x 15 = 6,750 cubic inches
Dimensional Weight Calculation: 6,750/166 = 41 pounds
In example 2, this is also a domestic shipment, so the cubic size in inches is divided by 166 to determine the dimensional weight, which is 41 lbs.
As in example 1, the dimensional weight here exceeds the actual weight, but because the cubic size of the package is larger than 5,184 cubic inches, the dimensional weight of 41 pounds will be used as the billable weight.
Example 3
Ship Method / Destination: Air / International
Actual Weight: 18 pounds
Length: 24 inches
Width: 12 inches
Height: 12 inches
Cubic Size Calculation: 24 x 12 x 12 = 3,456 cubic inches
Dimensional Weight Calculation: 3,456/139 = 25 pounds
In this last example, the package is being shipped internationally, so the cubic size is divided by 139 instead of 166, which makes the dimensional weight 25 lbs. This exceeds the actual weight of 18 lbs., and because it’s an air shipment and the 3 cubic foot minimum doesn’t apply, in this case the dim weight will again be used as the billable weight.
Dimensional weight can get a little confusing, and what makes it even worse is that, just when you think you have it figured it out, the carriers go ahead and change the rules (which means I’ll probably have to update this blog post before too long). And the problem with not correctly factoring in dimensional weight, is that you will likely get hit with back charges from the shipping providers.
While those USPS commercials make parcel shipping seem easy, in many cases it’s just not that simple, and that’s where an order fulfillment partner like eFulfillment Service can save you a lot of time and money.
Sick of dealing with the headaches of shipping? Let’s talk, we’d love to help.
What factor do I use instead of 139, to divide by if using metric dimensions?
Hi Colin,
That’s a great question. To calculate dimensional weight for U.S. shipments, I would recommend converting the dimensions of your package from centimeters into inches. This can be done fairly easily with a number of free tools online. Once you’ve converted the length, width, and height of your package into inches, you would then follow the same formula as described above. Then, once you’ve calculated the dimensional weight using pounds as the metric, you could then convert the dimensional weight back to grams or kilograms if you’d like.
Hope this helps.
Steve Bulger
Good day,
I’ve been working on a project and wanted to make sure that I’ve been moving in the right direction.
The task is the following : the video camera for film shooting purposes is required to be shipped from the US to Canada via air.Its dims are as follows: L x W x H , 85 x 78 x 45 cm,weight is 14 kg. The question is to determine if this camera shipment would be billed using the dimensional weight rule or actual weight?
I’ve converted the dims into inches and weight in to lbs.
Here are my calculations:
Length 85 cm or 33 inches
Width 78 cm or 31 inches
Height 45 cm or 18 inches
Actual weight is 14 kg or 31 lbs.
Volume: 33 x 31 x 18 (inch) = 18,414 cubic inches
Chargeable weight is 18,414 / 139 =132 lbs
Conclusion: Dimensional weight is greater than actual weight so it will be considered for billing.
Please advise if I were correct with my calculations.
Hi Valentina –
Thanks for the comment. I have reviewed your dimensional weight calculation, and yes, it appears to be correct.
If you visit the FedEx, UPS and/or USPS websites, they will ask for both weight and dimensions and will provide you with the available services and a quote for each. I would recommend checking DHL, as well.
Thanks,
Steve Bulger
I have read all the comments and the original post, but I was unable to understand the logic behind the numbers 166 and 139. Can u please tell in some detail that how do they come up with these numbers…? who sets these metrics and how?
Good question! FedEx and UPS set their own divisors to calculate dimensional weight. Regarding how they come up with those particular divisors of 166 and 139, it is likely based on a number of factors. Ultimately, though, the dimensional weight calculation helps to ensure these carriers are making the profit they want based on the size of their trucks, labor cost, fuel, etc.
Steve Bulger
If I have dimensional weight of 10 pounds. And I have 10 similar such boxes. Can I take that dimensional weight and multiply it with 10 to figure out the dimensional weight of 10 boxes all together. Or the dim weight is always calculated per box only and cannot be calculated for multiple boxes. If that’s the case than how do we find dimensional weight of 10 boxes or 100 boxes in a container.
Hi FJ,
That’s a good question. If you have multiple boxes as part of one shipment, the carriers will typically calculate the dimensional weight of each box, unless those boxes are banned or wrapped together, in which case they would calculate the dim weight based on the outer dimensions of the entire wrapped shipment. If you’re able to remove the units from each box and consolidate them all into one larger box, you may be able to reduce your dimensional weight.
Steve Bulger
My other question is that what is the difference between dimensional wight or cbm. For example one shipment can have cbm of 0.09 but dementional wight maybe 15 pounds. What the difference between these two.
Hi FJ,
CBM stands for cubic meter, which is calculated the same way as cubic feet, but obviously just in meters. Here in the U.S., FedEx, UPS and the U.S. Postal Service calculate the dimensional weight based on cubic feet, so if you know the box dimensions in meters, you’d simply have to convert those to feet.
Hope this helps.
Steve
guys it is very simple each courier company has there own calculation
total dimensional weight % 4000 or %5000 and you will get your total chargeable weight
i am working in a shipping company so i know how FedEx and other courier companies operate
I understand dim, but how do I know the actual weight of an item? Do I purchase a scale? Some of these items weigh 100 pounds (I’m guessing).
Other than lifting family members to judge the weight of larger items how would I find this out?
Hi Cheryl –
Thanks for the comment!
To calculate the actual weight, yes, you would need a scale. You could estimate the weight based on specs from your supplier, although, if the weight is incorrect, you’ll find that the shipping carrier, like FedEx or UPS, will later bill you based on the actual weight, and you may pay more than you thought. Once you have the actual weight, you can use the formula above to calculate the dimensional weight and see what the final shipping weight will be.
Thanks!
Steve Bulger
Question
If we have 16 pallets with different dimensions actual weight almost 9000 lbs total, can the carrier apply the dimension weight?
Hi Miguel –
Thanks for reaching out. And this is a great question. With these large freight shipments, dimensional weight often does not apply and the freight carriers will base the cost on the actual weight, along with other factors. The dimensional weight calculations outlined in this article are for smaller parcels that ship via FedEx or UPS Ground or Home Delivery.
Thank you,
Steve
The dimensional weight of a package is calculated by multiplying the length, width and height
Why we determine with 166 or 139???
Hi Akruti –
Thank you for the comment. And that’s a good question regarding the dimensional weight divisor that will apply to your orders.
This post is actually a bit older, and you’ll see an updated one here with the latest dimensional weight rules….
https://www.efulfillmentservice.com/2014/09/new-fedex-ups-dimensional-weight-rules/
With FedEx and UPS, the dim weight divisor is 139. With the U.S. Postal Service, it is 166 for ground shipments, although that only applies when shipping to zones 5-8 and when the package is larger than one cubic foot.
Hope this helps. If you have other questions on dimensional weight or our ecommerce order fulfillment services, please let us know!
Thanks,
Steve Bulger