Assigning the correct Royal Mail Postage Service for Large Letters & Parcels

Hi there,

I have a problem with orders being assigned the correct postage service via Royal Mail, and I can't imagine there are any other sellers without the same issue.

Alot of the products we sell are Royal Mail Large Letters & Parcels. I have been able to set up rules in the rules engine that automatically assigns the correct service based on a single product. It works something like this;

Default postage service is assigned. Order comes from marketplace --> Linnworks checks 1st or 2nd class --> Linnworks checks default service (parcel or large letter) --> Linnworks assigns that service.

Our problem is if someone orders a parcel product and a large letter product together, or orders 10 of a large letter product these would have to be sent as a parcel. Linnworks doesn't know to change this in the way I have it set up and we have to go into the order and edit it manually. I'm wondering if anyone has had problems the same?



Hello Ciaran,

 Thank you for your question. What I would suggest is to add another conditions check that would check either total weight or the item count.


 After this check is doen then you can go ahead and have rules engine assign the order to be shipped in a parcel. I've also checked your database and since you already have a massive rules tree built up then it would be a pain to add that one check before anything else. So in order to avoid editing the whole rule then I would suggest creating new rule and then assigning it as the first rule to be checked.


 Hopefully this solution works for you.

P.S. All pictures are from my test database.

With Best Regards,


Technical Support


 In addition to the first option, there is also an option to create "Packaging Groups" ("Shipping" -> "Packaging Group"). When creating a packaging group then weight range and dimensions can be set for each package separately.


 When setting up inventory items then default postage definition (dimensions and packaging group) can be added to the SKUs. Once an order comes in then, the appropriate packaging group will be assigned to the order based on the default settings. In case there are many items in the order then the prevalence of the packaging groups will determine which packaging group will be selected.


 For example, if order with two items (X and Y) come in with the same order and X has default packaging group selected as "Letter" and Y has default packaging group "Boxes" then boxes will be chosen for the order as it has the highest prevalence number in the system. Which box is selected for the order will depend on the order dimensions or weight (depending on which auto assignment method is in use).

 Furthermore, there are four auto assignment methods to pick from (that can be changed under "Settings" -> "General Settings" -> "General" -> "Packaging selection method"). Legacy Desktop Compatible, Take Maximum Dimensions of Order Items, Stack Items Vertically and Fit into Packaging by Weight. Which type is best for you depends on what type of products you sell and how you usually ship them.

More reading on the topic:

Documentation on auto assigning packaging groups:

Documentation on product postage definition:

Hope this helps.

With Best Regards,

Technical Support

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