As for the delivery of parcels, you might encounter such a situation: your package weighs 10kg, but you are charged for 20kg. Actually, this is because logistics companies compare the volumetric weight and actual weight, and charge fees according to the larger one.

If your shipments are lightweight but cover a large space, you’ll be charged by the volumetric weight. It is essential to know what volumetric weight is and how to calculate it. This will affect your freight costs.

In today’s post, I explain volumetric weight in a practical way. Let’s get started.

What is Volumetric Weight or DIM Weight?

Volumetric Weight = Volume Weight = Cubic Weight = DIM Weight = Dimensional Weight

Volumetric weight is the shipment’s “virtual” weight calculated by a conversion of the volume. It is used to charge shipping fees for lightweight but large-sized goods.

Suppose there are 2 batches of goods: 15kg iron and 15kg garments. The latter takes up a much larger space. To transport goods with the same gross weight, the one occupying more space should be charged more, because the loading space of transport tools is limited. This is just like you need to pay more for additional seats when booking airline tickets.

So logistics companies would measure the garments’ package size — 60*50*40cm to calculate the total volume and convert that into the volumetric weight — 24kg to charge fees and cover the extra running cost.

Volumetric Weight vs Actual Weight

Actual weight is the real total weight of goods including packaging. In other words, it is the gross weight appearing on a weighing scale.

Compare the actual weight with the dimensional weight, you’ll find that,

  • Actual weight > dimensional weight, freights will be charged by actual weight. Such goods are called Heavy Products or High-Density Items.
  • Actual weight < dimensional weight, freights will be charged by dimensional weight. Such lightweight but big-sized goods are called Light Products or Low-Density Items.

Therefore, it’s clear to us that the larger of the two is used to calculate freight charges, known as chargeable weight or billable weight.

Generally, light products are charged by volumetric weight. Common examples include clothing, quilts, shoes, bags, suitcases, pilots, plush toys, paper items, etc.

When a batch of goods consists of heavy and light products, the billable weight shall be the total actual weight or the dimensional weight of this batch, whichever is larger.

What is The Formula for Dimensional Weight Calculation?

There are 2 ways to calculate dimensional weight, one is total shipment volume / DIM factor, and the other is total shipment volume in CBM * conversion ratio. You can choose the method that works best for your situation. Let’s have a look one by one.

Formula 1: Dimensional Weight = Total Shipment Volume / DIM Factor

Total Shipment Volume Calculation Formula

To calculate your shipment’s volume, you need to figure out whether your packaging boxes are regular, irregular, or cylindrical. Because this affects how you calculate the package’s volume.

1. For regular packages like cube and cuboid boxes,

Total Shipment Volume = (Length × Width × Height) x Quantity

Note: if the regular carton swells and bulges due to cargo extrusion, as shown in the below image, it shall be calculated according to the longest side of the carton.

how to calculate the volume of regular carton that swells and bulges
  • Before packing goods, measure the carton’s external dimensions: L — 15 cm; W — 30 cm; H — 20 cm.
  • Due to cargo extrusion or any part that protrudes, measure the package: L — 18 cm; W — 33 cm; H — 22 cm.
  • Here the volume = L x W x H = 18×33×22

2. For irregular packages,

Total Shipment Volume = (Longest Length x Longest Width x Longest Height) x Quantity

3. For cylindrical packages,

Total Shipment Volume = (π x r² x h) x Quantity

  1. Round up each measurement to the nearest whole number. For example, 5.8 will be considered 6.
  2. Logistics companies measure all packages at the longest or most protruding point. It might be larger than the size marked on cartons, because packages may be deformed in the process of loading, transportation, and unloading. But the measurement difference won’t be too large, whereby 1-2cm is normal.

DIM Factor

A DIM factor, also known as the DIM divisor, is a number set by carriers to identify the volume of a shipment allowed per unit of weight. The DIM factor varies with different shipping methods and measuring units. For international shipments, the most common DIM factors include,

Using CM and KGUsing inches and Ibs (pounds)
6000 — Air Freight166 — Air Freight
5000 — Express Freight/Courier139 — Express Freight/Courier

In the express industry, different carriers have different ratios for the conversion of volume. Currently, 4 major international express delivery giants, including FedEx, UPS, DHL, and TNT, apply the DIM divisor 5000.

Some express carriers use the divisor of 6000 or 7000. For instance, Hong Kong DHL-6000 sets the number to be 6000, which makes it cheaper to deliver low-density products. The higher the DIM factor, the lower the DIM weight, which usually means lower shipping charges.

Additionally, whether the shipment is domestic or international might influence the volumetric factor. Take FedEx for example. It uses a volumetric factor of 166 for domestic packages measured in inches, while this figure is 139 for international shipments.

Last but not least, DIM divisors are subject to variation. Strongly suggest you consult logistics service providers or sourcing agents for the latest and most accurate info.

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Formula 2: DIM Weight = Total Volume (CBM) * Conversion Ratio

To convert CBM into DIM Weight, the ratio is:

Air freight: 1 CBM = 167 KG

Express Freight/Courier: 1CBM = 200 KG

Sea/ocean freight will not restrict the weight per unit of volume as strictly as the express or air shipments. Typically, for FCL sea freights, it just needs to ensure that the cargo weight is within the maximum payload of shipping containers. When it comes to LCL sea freight, the common conversion ratios cover,

  • 1CBM=1000KG
  • 1CBM=750KG
  • 1CBM=500KG
  • 1CBM=363KG

Which conversion standards should you use? Contact us for answers and our Jingsourcing experts will help you ship products at the most cost-effective price.

Live Example to Calculate DIM Weight & Freight Charges for Courier/Air Shipments.

To know courier or air shipments’ costs, it is necessary to calculate the DIM weight and compare it with the actual weight. And the heavier one will be the chargeable weight.

Once you know the formula, it is easy to calculate the DIM weight. Here I use 2 examples to show you how to figure out the DIM weight and freight charges step by step.

Example 1: An English client purchases a batch of diaper bags from China. This batch of goods has been packed into 15 regular carton boxes, and one carton weighs 7 kg. The shipping solution can be air freight or 4 major international express delivery giants.

Step 1: Check Total Gross Weight

The total gross weight: 7 kg * 15=105 kg

Step 2: Measure The Package and Calculate The Dimensional Weight

Generally, you can know the carton size by directly asking your Chinese supplier, who would measure the package in cm. Here are the carton measurements.

  • L — 44.8 cm, which rounds up to 45 cm.
  • W — 37.6 cm, which rounds up to 38 cm.
  • H — 35 cm.

Total shipment volume = (L*W*H) * quantity = (45 x 38 x 35) x 15 = 897,750 cm³ = 0.89775 m³

To calculate the DIM weight, you can divide the total volume (cm³) by the DIM factor, or multiply the total volume (m³) by the conversion ratio. 

If shipped by express

DIM weight = 897,750 cm³ / 5000 = 0.89775 m³ x 200 = 179.55 kg.

Round it up to the next half number 180 kg, as the rates change at each half-kilogram.

If shipped by air

DIM weight = 897,750 cm³ / 6000 = 0.89775 m³ x 167 ≈ 150 kg.

Step 3: Determine Billable Weight

  • By express, the DIM weight of 180 kg > total gross weight of 105kg.
  • By air, the DIM weight of 150 kg > total gross weight of 105kg.

Either way, the billable weight is DIM weight.

Step 4: Calculate Freight Charges

Freight charges = billable weight x freight rate. 

Here we suppose the freight rate to be $6.5 per kg for express and $5.5 per kg for air.

  • By express, freight charges = 180 x 6.5 = $ 1,170
  • By air, freight charges = 150 x 5.5 = $ 825

Example 2: An Amazon FBA seller sources a batch of shoes from China and needs to ship products to the warehouse in the Western US. For this batch, 12 pairs to one carton, with a total of 40 regular carton boxes. The single carton weighs 12 kg and is measured as Length — 49 cm; Width — 42 cm; Height — 39 cm.

In this example, we can still use the above 4 steps for calculation.

Actual Weight: 12 kg x 40=480 kg

Total Shipment Volume Calculation: 49 x 42 x 39 x 40 = 3,210,480 cm³ = 3.21048 CBM

Dimensional Weight Calculation:

If shipped by express

DIM weight = 3,210,480 cm³ / 5000 = 3.21048 CBM x 200 = 642.096 kg. Rounds up to 642.5 kg.

If shipped by air

DIM weight = 3,210,480 cm³ / 6000 = 3.21048 m³ x 167 ≈ 535.5 kg.

Either way, the chargeable weight is the DIM weight, which is larger than the actual weight.

As mentioned earlier, for cargo above 500kg, air freight is more cost-effective than express. So here we just figure out the air freight charges.

Suppose the freight rate is $5.5 per kg for air, air freight charges = 535.5 x 5.5 = $ 2,945.25

In practice, you might hear that freight forwarders will combine lightweight and heavy parcels into one air shipment to make full use of the space and make more profits.

Suppose that a freight forwarder has booked a space and collected a lot of heavy products, and you have a batch of big-sized but light-weighted products to ship. At this time, the forwarder will be very willing to ship your products together with his heavy goods in the same shipment.

In this case, if he only ships heavy goods, he will waste much space. But if adding your goods, he can make use of the left space but won’t increase much chargeable weight. So he just needs to pay the airline a little more to ship this batch of consolidated shipments, but he can charge you and other heavy cargo owners at the same time.

To get your goods, usually, freight forwarder will cut 30% or 50% of profits to you. Still use example 2 and suppose he agrees to sacrifice 50% of profits. In this way, your chargeable weight is not 532 kg, but “532 – [(532-480)*50%] = 506 kg”. For you, this is cheaper.

Here you can use the following formula to get the final chargeable weight.

Final chargeable weight = DIM weight – [(DIM weight – actual weight) x percentage]

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Live Example to Calculate DIM Weight & Freight Charges for “Sea Freight Plus Courier”.

Typically, ordinary LCL sea freight is suitable for cargo over 2 CBM. So for the above example 2, whereby the shipment is around 3.2 CBM, LCL sea freight is the cheapest shipping method without considering the delivery time.

However, if Amazon‘s seller in the case can wait about 25 days at most, it is advisable to use “Sea Freight UPS Combined”. This solution is cheap but faster than ordinary sea freight.

In this case, we can still use the above 4 steps to calculate the DIM weight and freight charges.

Under the “sea freight plus courier” shipping mode, shipments are generally charged per kilogram, different from the ordinary sea freight charge by CBM.

Here suppose that the freight forwarder offers a quotation: $3.5 per kg.

Dimensional Weight Calculation: the total shipment volume / DIM factor = 3,210,480 cm³ / 6000 = 535.08 kg. Round up to 535.5 kg.

Since the DIM weight of 535.5 kg > the actual weight of 480 kg, the sea freight is charged by the DIM weight.

“Sea Freight UPS Combined” Freight Charges = 535.5 x 3.5 = $ 1874.25

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The End

Reading here, I believe you would better understand the DIM weight and how it affects your shipping costs. Should you have any queries, just leave a quick comment below.

To reduce the shipment’s dimensional weight and thus save money, people usually simplify packaging and/or ship light items together with other orders of heavy items. Contact us if you need such services.

We are Jingsourcing, a leading Chinese sourcing company with rich experience in product sourcing, packaging, and shipping. Tell us your needs and enjoy our high-quality services at a competitive price.

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