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Volumetric weight rates: shipping calculator for WooCommerce

In this post we will explain the volumetric weight meaning, how to setup it on Fish and Ships, and give you an online volumetric weight conversor and a volumetric weight calculator. All you need to success on volumetric or dimensional weight. 😉

Most parcel companies base their rates (or at least some of their rates) on volumetric weight table rate. At first it may seem confusing, but is so logic and easy to understand. With Fish and Ships (pro version) it will be easy as a piece of cake.

The volumetric weight meaning

Imagine a shipping rate based on weight only. Then, some product, so big and lightweight, let’s say foam for isolation. For the parcel company, it takes up a lot of space in their warehouses, airplanes, vans… right? So, imagine a shipping rate based only on volume, and a product really weight and mid-sized, like anvil… there is a way to cover all cases in a unique shipping table rate? Yes, there is… the volumetric or dimensional weight.

The volumetric weight gets the volume of the package and multiplies by a volumetric weight factor. With it, we have a value, named volumetric weight. This value will be compared with the package weight. And the bigger value will be result of the volume weight calculator.

There is: for small products, weight will be get as volumetric shipping weight, and for big volume products, volumetric weight will be used: the biggest one.

WooCommerce volumetric shipping

Okay, but… how this will work into WooCommerce volumetric shipping? Each parcel company will be give you his own volumetric weight factor. Fish and Ships will use his internal volumetric weight calculator: will get the products size, run his in-built volume weight calculator, compare with product weight, and get the biggest of this.

When you set the first volumetric weight selctor on shipping method settings, a new field will appear at the bottom of the shipping table rules: the volumetric weight factor input.

The volumetric weight factor input field
The volumetric weight factor input field

Volumetric weight conversor

Fish and Ships use your shop units for WooCommerce volumetric shipping calculation: What you’ve set on WooCommerce settings: the weight and the dimensions unit (cubic). So expects the volumetric weight factor in your shop units.

Sometimes the volumetic weight factor units aren’t the same as you use in your WooCommerce shop. In this case, you must convert this to your shop units. This are a bit tricky, because volume are a cubic unit, for example, 1 m3 = 1000 dm3 = 1.000.000 cm3.

…and things being a bit more complicated with the DIM format: isn’t the same 10 kg/m3 (every cubic meter weighs 10kg) than 10m3/kg (10 cubic meters weighs 1kg)…

Fortunately, we have for you a volumetric weight conversor: simply choose your parcel weight format on the top. Then enter the volumetric weight factor value with his units (weight and volume). And set your shop units below: The weight factor will be converted. Copy it and paste in your shipping method settings:

First, introduce your parcel company DIM format:

weight/volume   volume/weight

Now, the volumetric weight factor in the parcel company units:

3 /

Volumetric weight factor in your shop units:

... 3 /

Volumetric weight calculator

Fish and Ships comes with a built-in volumetric weight factor calculator. However, if you need to calculate manually for any reason, here you can do it:

Set your shop units and enter your parcel volumetric weight factor. Then, put the size and weight of your product. The volumetric weight calculator will does the job, in the same way as does Fish and Ships does. Also, you can convert the volumetric weight to your parcel weight unit again, if you need it:

First, introduce your shop units:

Size unit: Weight unit:

Now introduce the Volumetric weight factor in your shop units:

m3/kg Need conversor?

Your product dimensions:

m m m kg

Volumetric weight calculator result in your shop units:


Need to convert volumetric weight to your parcel units again?


A real world example

Here a shipping table rate, volumetric or dimensional weight based:

WeightShipping rate
Up to 20Kg10.50 €
From 20 to 50 Kg25.00 €
From 50 to 100 Kg40.00 €
From 100 to 300 Kg60.00 €
Volumetric shipping weight

…with a volumetric weight factor of 5000 cm3/kg

How dimensional weight calculator works?

Let’s say we have two different products: one big and lightweight and another small and weight. The biggest value beteen real weight and calculated from volume weight, will be used to set the shipping rate:

ProductSizeReal weightVolume weightVolumetric / Dimensional weight calculatorShipping rate
Foam isolation100x100x60cm30 Kg100x100x60 / 5000 = 120Kg120Kg60.00 €
Anvil70x40x4060 Kg70x40x40 / 5000 = 22.4 Kg60 Kg40.00 €

The first product, lightweight and voluminous will set his shipping price per volume, they pay as 120kg weight. The second one, so weight but small, will pay per weight.