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FAQ: How Do I Calculate Dimensional Weight?


FAQ: How Do I Calculate Dimensional Weight?

published on 29.11.2012 in Blog by

UPDATEThe 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:

Domestic Shipments
Dimensional Weight Domestic Packages

International Shipments

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.

How Do I Calculate Dimensional Weight?
Article Name
How Do I Calculate Dimensional Weight?
Determining the shipping cost of a package isn't always easy, especially when dimensional weight comes into play. In this post, we discuss how to calculate dimensional weight, and when it's applied.
eFulfillment Service

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42 Responses to “FAQ: How Do I Calculate Dimensional Weight?”
  1. Raj Patil says:

    I ordered a product (LED TV) online that’s being shipped by Fedex now. The TV weighs 11.5 Kgs as from online info. So including the pkg it would weigh 12 kgs at minimum. But Fedex informing me that it is just 10kgs as dim weight. The dims are: 82x58x15. How is it now??

    • Steve Bulger says:

      Hi Raj, thank you for the comment. Dimensional weight is something that can occasionally be negotiated with the carriers, so it may be that the retailer you purchased your TV through has done so. It may also be that FedEx is simply mistaken and that the billable weight was indeed much higher than 10kgs, which will be picked up by the retailer.

  2. james says:

    Does anyone regulate and approve the mathematics and formulator divisors? How did they come up with the number of 166 for the public and Why don’t they use 194 as the us postal service does, for zone shipping?

    • Steve Bulger says:

      Hi James, thank you for the comment.

      FedEx and UPS do not have the same sort of regulatory review process as the USPS, which is a government agency. Therefore, there is no independent regulatory body that would mandate how FedEx and UPS operate their business from a pricing standpoint, including with their dimensional weight rules and pricing.

      As far as how they came up with 166 as the DIM divisor, that’s a good question. It’s basically a formula that their math whizzes came up to ensure they’re making their desired profit given the size of their trucks and the associated costs they incur for delivery. Ecommerce order fulfillment has been growing over the last few years, and as a result, these carriers are seeing more large packages that are relatively lightweight. So their old method of only charging for shipping based on actual weight was no longer viable.

      As to why they don’t use the same DIM divisor as USPS, one reason is that the U.S. Postal Service, being an independent government agency that is legally required to serve all Americans, has a network that is set up to deliver to millions of residences every day. Their dimensional weight divisor of 194 also only comes into play when shipping to zones 5-8 and when packages are over 1 cubic foot. The reason for this is that, when shipping to a zone 5 or higher, the USPS actually uses FedEx airplanes to help deliver Priority Mail packages.

      Hope this helps!

      Steve Bulger

    • Dave says:

      I think it stays fairly well regulated by those in the shipping and 3PL industries. If rates and dims got out of control from our vendors then we would go elsewhere to better rates.
      Our company uses the 194 dim, but many of our carriers use the 250 dim factor.

  3. Delores Lyon says:

    Oh wow, I had no idea that there are so many regulations for freight dimensional weight. It shows just how important it is to use a freight company that has easy-to-follow rules. I know I wouldn’t want to hire a company that had convoluted rules like this.

    • Najma Qureshi says:

      Delores Lyon
      The reason is shippers have to choose the packaging that relates closely with the product inside because the cost associated with wasted space significantly affects the delivery price.

  4. praveen kumar says:

    hi, can i have the solution, how to calculate a shipment weight while booking by CHA and loaded into an container.

    • Steve Bulger says:

      Hi Praveen, thank you for your comment. If you’re using a customs house agent and shipping a full container, dimensional weight may or may not apply. Your freight company or customs broker will be able to provide you with a total cost once you have the actual shipping weight, pallet dimensions, product type and destination, including the actual transit costs as well as customs and duty fees.

      Steve Bulger

  5. Prasad k s says:

    How are you determining 139 for International and 166 for domestic couriers. Can we know the arriving calculation for the same.

    • Steve Bulger says:

      Hi Prasad –

      Thanks for the comment. The dimensional weight divisors of 139 for international shipments and 166 for domestic shipments are the standard DIM divisors for UPS and FedEx. For inbound shipments, the calculation may be different and is dependent on the size/weight of your shipments, as well as the shipping or freight company you are using. If you have a specific shipping example, I can try to provide more details.

      Please let me know how else I can help.

      Steve Bulger

  6. Ross R says:

    Hi, I am a domestic courier contractor in Canada. We use 166 for dim.

    My understanding of dim weight is that the calculation used will bring you to a weight per cubic foot that would be fair and reasonable for all involved. For example, If someone were to ship a truck full of pillows and I were to drive two hours to a resort to deliver them, billing on actual weight would not even cover the fuel, therefore, dim weight comes in to play. We would use that dim weight as a starting number to negotiate from until a fair price is arrived at,ie dim weight x .6 so that everyone stays profitable.

    I just wanted to point out that it is not a profit scheme, but a way to level the playing field.

  7. SWAJON says:

    Please let me know about the numbers 166 and 139. How do you get these numbers?

    • Steve Bulger says:

      Thank you for your question. The numbers 166 and 139 represent the divisors that the carriers use to calculate dimensional weight. For example, if the package is 12 inches x 12 inches x 12 inches, the total cubic volume is 1,728 inches. FedEx and UPS would then divide this number by 166 to determine the dimensional weight for ground shipping, which would be 10.4 pounds, and they would divide it by 139 to determine the dimensional weight for international shipping, which would be 12.4 pounds.

      FedEx and UPS update these divisors from time to time. For example, next year, in 2017, FedEx has announced that the dimensional weight divisor will be 139 for both ground and international shipments, which will, of course, increase the dimensional weight for ground shipments.

      Hope this helps!

      Steve Bulger

      • vibha says:

        If its a shipment by road i would like to know the following.please help.
        Shipment by: Road
        Dimensions: 4.5′ X 3.5′ X 3′
        Actual Weight: 350 lbs
        Calculate the volume: ___
        Calculate the dimensional weight:

        Please show your working for your dimensional weight calculation Include all units of measurements.
        this way i will understand better

        • Steve Bulger says:

          Hi Vibha,

          Thank you for your comment.

          The calculations above for dimensional weight apply to standard ground and home delivery services from FedEx and UPS. With these shipping services, the weight limit is 150 pounds. Therefore, with the shipment you described, it would be required to ship via freight. The dimensional weight calculations can vary with freight companies, although, at a weight of 350 lbs for a shipment that is only about the size of one pallet, dimensional weight likely would not apply in your case when shipping freight.

          Steve Bulger

  8. Glenn O'Brien says:

    In Australia and New Zealand, the dimensional weight is 250 kilograms per cubic meter for domestic consignment, and 200 kilograms per cubic meter for international consignment.

    URL: http://www.tollgroup.com/lookups/cubic-volumetric-calculator

  9. Hitendra kumar Jashbhai Patel says:

    I have 43″LED I want to carry in international it’s length -106 cms/width -16 cms/height-68 cms please give me idea for dimensional weight.

    • Steve Bulger says:

      Hi Hitendra –

      Thank you for reaching out. The dimensional weight calculation is dependent on the specific shipping carrier that you’re using. If you’re using one of the two most common carriers (FedEx or UPS), they have a dimensional weight divisor of 139 when shipping internationally. Therefore, your package, which, translated to inches, is 41.7 in. x 6.3 in. x 26.8 in., would have a dimensional weight of 51 pounds. You would have a lower dimensional weight with the U.S. Postal Service, as their dimensional weight calculation is based on a divisor of 166.

      Hope this helps!

      Steve Bulger

    • Richard Lynn Paul says:


      multiply them and divide by 5,000, so 23.0656 which rounds to the next 1/2 kg or 23.5 kg (and my physics teacher would scold me for not putting all my units in the work).

  10. Shashikant sant says:

    I have the product dimensions i.e. Height, Length
    so i have calculate the dimensional size of Wrapper have to be used, size means Width and Length
    (Products in Oval shape).

  11. Colin says:

    What factor do I use instead of 139, to divide by if using metric dimensions?

    • Steve Bulger says:

      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

  12. Valentina says:

    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.

    • Steve Bulger says:

      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.

      Steve Bulger

  13. Waqas Zafar says:

    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?

    • Steve Bulger says:

      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

  14. FJ says:

    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.

    • Steve Bulger says:

      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

  15. FJ says:

    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.

    • Steve Bulger says:

      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.


  16. abdul says:

    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

  17. CHERYL ODOM says:

    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?

    • Steve Bulger says:

      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.

      Steve Bulger

  18. Miguel Lopez says:


    If we have 16 pallets with different dimensions actual weight almost 9000 lbs total, can the carrier apply the dimension weight?

    • Steve Bulger says:

      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,

  19. Ricky says:

    The dimensional weight of a package is calculated by multiplying the length, width and height

  20. Akruti Hansaliya says:

    Why we determine with 166 or 139???

    • Steve Bulger says:

      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….


      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!

      Steve Bulger

  21. Rebecca Gardner says:

    Thanks for explaining that it’s common practice to round to the nearest whole number when dealing with dimensional weight. My brother is looking for some Gaylord boxes he can use to hold and store his manufacturing materials during transportation. I’ll pass along this info to help him learn about the practices used while transporting boxes!

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