Letterbox Packaging

Letterbox packaging and letterbox mailings are becoming increasingly popular, as they provide a cost effective way of delivering goods. They avoid the complications of signing for a parcel, and paying for a large package that isn’t needed. They are generally manufactured from cardboard. Why not click here to read our blog all about cardboard boxes!


It’s possible to send a vast assortment of products, such as flowers, custom greeting cards and make up subscription boxes. You can see why people are choosing this option when there are potentially huge savings in postage! We’ll give you all the best tips on getting the best value for money in letterbox packaging and posting.

Why choose Letterbox Size Boxes?


Switching to letterbox sized boxes not only saves you money – it also creates a better experience for customers. Not having to wait in, sign for it whilst working from home or collect from the local depot will make the process so much easier for them!


To make the switch to more cost effective posting, start by evaluating your products. Which ones could be packaged in a way to make them letter box compatible? Once you’ve established that, you can start to look at box sizes and postage costs.

What is the standard UK Letterbox Size?


Although letter box sizes in the UK can vary slightly, the standard size of 254mm x 38mm is widely used. 


To create a successful letterbox delivery, ensure your box is smaller than these dimensions. The next aspect is to consider how much the mailing will cost. Thinner boxers could be classed as a large letter, which will make your postage even cheaper. This applies to boxes 25mm thick and less.

Where can I find Letterbox Boxes?


Springpack can make the complicated world of cardboard letterbox boxes much easier! We have a range of standard UK letterbox size boxes for you to choose from, just head over to our website to take a look.


If you can’t find what you’re looking for, give the Packaging Pros a call on 01905 457 000. They’ll be able to point you in the right direction!

What is the Royal Mail Letterbox Size?


Shipping costs will vary depending on their size and weight, it’s not just about whether the parcel will fit through a letterbox or not.


Royal Mail advise that an item can be classed as a large letter if it weighs less than 750g and measures up to 353mm (L) x 250mm (W) x 25mm (H). We have a great blog on the Royal Mail’s Pricing in Proportion guide, so take a look to find out the best option for your box.



If you’re looking for more help and advice on your letterbox packaging, we’re here to help. Call the Packaging Pros on 01905 457 000 or email us on [email protected].

About the author

Profile image of Simon Rees
Simon Rees
I am Springpacks Head of Marketing covering all aspects of marketing. I specialise in digital marketing with almost 15 years experience.
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