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How to Calculate Dimensional Weight for Your Package

How to Calculate Dimensional Weight for Your Package

You know the drill - you've got a fantastic product, you've secured an order, and now you have to get it out to your customer. But, here's the catch - shipping isn't just about tossing your goods in a box and sending it off with a pat on the back. If only it were that simple!

Ever wondered why your shipping costs sometimes seem way higher than you expected? Enter the subtle science of dimensional weight or DIM weight. Shipping can sometimes feel like a maze, especially when it comes to figuring out the dimensional weight. 


To calculate the dimensional weight for your package, you need to understand the concept of dimensional weight, gather the package measurements of length, width, and height, calculate the volume by multiplying the dimensions, determine the dimensional weight factor used by your shipping carrier, divide the volume by the dimensional weight factor to obtain the dimensional weight, and compare the actual weight with the dimensional weight to determine the chargeable weight.


In this article, we're going to break down how to calculate the dimensional weight of your package, so you can ace your shipping game while being kind to your wallet. Ready to get started? Let's dive in!

1. Understand the Concept of Dimensional Weight

Dimensional weight is a pricing technique used by shipping companies. It's not just about the actual weight of the package - the size matters too! Why, you ask? Well, you know, a large fluffy teddy bear may not weigh much, but it can take up a whole lot of space in the delivery truck.

So essentially, dimensional weight is a balance between the weight of the package and the space it occupies in the shipping vehicle. Shipping companies adopted this method to ensure they’re being fairly compensated for the space that your light and bulky package takes up, whether it's light as a feather or heavy as a brick.

Think about it: if they charged only by actual weight, they could lose money when transporting light but bulky items that take up a large amount of space. On the other hand, if the dimensional weight exceeds the actual weight, carriers may charge based on the higher value.

The concept of dimensional weight helps shipping companies use their space more efficiently and encourages us, the shippers, to pack our products more compactly. Understanding and calculating dimensional weight can help you optimize your packaging to reduce shipping costs, a saving that can be passed on to your customers or reinvested into your business.

Learn more about the difference of actual weight vs dimensional weight here: 

2. Gather the Required Measurements

To calculate dimensional weight accurately, consider the package dimensions and gather the following measurements:

  • Length: Measure the longest side of the package.
  • Width: Measure the side perpendicular to the length.
  • Height: Measure the remaining side, perpendicular to both the length and width.

Remember, you need to measure the box or envelope as it is, meaning don’t bulge out the sides or squeeze it in. Keep it natural. Also, use the same unit of measurement (inches or centimeters) for all dimensions.

3. Calculate the Volume of the Package

Calculating the volume of your package is as simple as multiplying its length, width, and height. Here's the formula:

Volume = Length x Width x Height

For example, if your package is 10 inches long, 8 inches wide, and 4 inches high, you would calculate volume like this:

Volume = 10 inches x 8 inches x 4 inches = 320 cubic inches

Remember, different shipping companies may use different measures. While some use inches, others may use centimeters. Make sure you know the unit of measurement your courier uses and convert your numbers if needed.

4. Determine the Dimensional Weight Factor

Before you calculate the dimensional weight of your package, you need to determine your shipping carrier's dimensional weight factor first. This crucial number plays a vital role in your calculations, so it's important to get it right

The DIM factor is a constant set by shipping couriers that helps convert the volume of your package (in cubic inches or centimeters) to a weight equivalent. Different shipping companies may use different DIM factors, so make sure to check this with your service provider.

For instance, FedEx and UPS use a DIM factor of 139. This is what we'll be using for our calculations moving forward. 

5. Calculate the Dimensional Weight

Now that you have your DIM factor (for our example, we're using FedEx's DIM factor of 139), you can begin calculating the dimensional weight.

To calculate the dimensional weight, you need to divide the volume of your package by the DIM factor. Here's the formula:

DIM Weight = Volume / DIM Factor

With the volume of your package in cubic inches (that you calculated from the package's length, width, and height) and your determined DIM factor, fill in the values:

If we stick with our example and the volume of your package is 320 cubic inches, the calculation would look like this:

DIM Weight = 320 cubic inches / 139 = 2.3 lbs

It is good to note that for shipping purposes, shipping companies usually round up the dimensional weight to the next whole pound. Hence, in our case, your package’s dimensional weight would be rounded up from 2.3 lbs to 3 lbs.

6. Compare Actual Weight and Dimensional Weight

To determine the chargeable weight, compare the actual weight of your package with the calculated dimensional weight. Shipping companies usually charge you based on the higher of either the actual weight or the dimensional weight.

The table below shows you the importance of considering both the size and weight of your package. Please take note that the dimensional weight here was calculated using a DIM factor of 139. This factor, however, may vary from one shipping company to another. 



(L × W × H in inches)

Actual Weight (lbs)

Calculated Volume

(cubic inches)

Calculated Dimensional Weight


Charged Based On


10 × 10 × 10



7.2 (rounded up to 8)

Actual Weight


20 × 20 × 20



57.6 (rounded up to 58)

Dimensional Weight


5 × 5 × 5



0.9 (rounded up to 1)

Actual Weight


15 × 15 × 15



24.3 (rounded up to 25)

Actual Weight


18 × 18 × 18



42 (rounded up to 42)

Dimensional Weight

7. Optimizing Dimensional Weight

You've now got the hang of determining dimensional weight. But knowing how to use this knowledge effectively is where the real power lies. This is where optimizing dimensional weight plays a key role. 

The goal here is to pack your products in a way that's not only safe but also space-efficient. By doing this, you can reduce shipping costs, especially if your business frequently ships lighter, larger items. 

Here are some tips to help you optimize:

  • Selecting Appropriate Packaging: Choose packaging solutions that are compact but still offer enough protection for your items. Remember, saving on space shouldn't mean compromising the safety of your products during transit. 
  • Removing Excess Space and Padding: Cut down on unnecessary voids in your packages by using eco-friendly packaging materials that fit snugly around your items, offering protection without wasting space.
  • Efficient Box Selection: Select boxes that are the right size for your items to get rid of excess empty space. Using a box that's too large for your product will only add to the dimensional weight. 
  • Multi-depth Boxes: These are designed to be cut down to the size you need. They're a versatile option that can help you reduce dimensional weight.
  • Custom-Made Packages: For frequently shipped items, consider investing in custom-made packages. They might cost more upfront but can lead to significant savings in the long run.
  • Consolidating Items: If possible, try to combine multiple items into a single shipment. This can sometimes help reduce the overall dimensional weight, which lowers the shipping costs.

Just remember, while cost-saving is good, it shouldn't come at the expense of your products' safety. A damaged item is definitely worse for your customer than a slightly higher shipping fee. Striking the right balance is key. 

Delivering Success with Smart Shipping Practices

The subtleties of shipping are just as important as the product you're delivering. Knowledge of things like dimensional weight can give you that extra edge, which helps you to make smarter decisions and stand out from the crowd. Once you understand the concept and follow the steps outlined above, you can ensure fair pricing and optimize your shipping costs. 

Ready to pack with a punch? Check out our range of eco-friendly packaging supplies, and let's reshape the way we ship together! Our biodegradable mailer bags come with beautiful designs, so you can ship your products in style while staying true to your commitment to sustainability. Our water-activated tapes are also made from renewable materials and are biodegradable, ensuring that they leave a minimal impact on our planet. 

Because, after all, great things come in well-packed, sustainable packages! Shop now!

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