Royal Mail Parcel Sizes Guide

The Royal Mail size and weight guide for the UK is a handy reference of the standard dimensions of letters and parcels in the UK for when you are sending products through the post.

Knowing the size of your packaging is important as if you are sending goods in packaging that is larger than needed could cost you a lot of money in the long run.

The Royal Mail splits the level of postage charges between letters and parcels.

The two different sizes of letter are ‘Letter’ and ‘Large Letter’. There are three types of parcel size: ‘Small Parcel’, ‘Medium Parcel’ and ‘Large Parcel’.

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Royal Mail Parcel Sizes – UK

Format Max weight Max length Max width Max thickness/depth
Small Parcel 2kg 45cm 35cm 16cm
Medium Parcel 20kg 61cm 46cm 46cm
Large parcel – via Parcelforce Worldwide 30kg 1.5m 3m length and depth combined
Tubes Length of the item plus twice the diameter must be less than 104cm, with the greatest dimension less than 90cm.

Small Parcels

Royal Mail small parcels are up to 450mm x 350mm x 160mm in size with a maximum thickness of 160mm and a weight limit of 2Kg.

The small parcel size would allow you to send a candle for example in an 0201 single wall box with dimensions of 152 x 152 x 102mm. You could also send a subscription box in an 0426 die cut box (250x200x100mm).

Take a look at just some of the small boxes we offer that could be posted as small parcels by the post office.

Medium Parcels 

Royal Mail medium parcels are up to 610mm x 460mm x 460mm in size with a maximum thickness of 460mm and a weight limit of 20KG.

In terms of size, the boxes we recommend for 13 inch laptops would easily stay under the size limit, unless you have a lightweight laptop that weighs under 2KG, you will be charged for a medium parcel.

Large Parcels

Royal Mail large parcels are classed as bigger than 610mm x 460mm x 460mm in size or weigh in at more than 20KG.

Our double walled large boxes are ideal for transporting heavier goods being both sturdy and durable.

What is the Biggest Size Parcel the Post Office Will Take?

The biggest parcel the Royal Mail Post Office will take is one not larger than 2.5m length and 5m length and girth combined that weighs 30kg or less. Large parcels are sent via ParcelForce Worldwide.

Custom Parcel Boxes

We can produce custom sized packaging that not only will make sure you’re sending your goods in the optimal sized box but also provide your customers with a unique branding experience.

Royal Mail Letter Sizes – UK

Format Max weight Max length Max width Max thickness/depth
Letter 100g 24cm 16.5cm 5mm
Large Letter 750g 35.3cm 25cm 2.5cm


Royal Mail letters have a maximum length of 240mm, a maximum width of 165mm with thickness up to 5mm and a weight no more than 100g.

Large Letters

Royal Mail large letters have a maximum length of 353mm, a maximum width of 250mm with thickness up to 25mm and a weight no more than 750g.

Mail lite envelopes that fit the large letter dimensions would be perfect for sending a DVD or a mobile phone as they contain bubble wrap to protect the goods and also will be cheaper to send than a box.

Royal Mail Prices

Royal Mail have produced a Business Price Guide that contains parcel and letters pricing and also details of other services such as franking and internal postage.

Personal customers and marketplace seller prices are covered by their UK and International parcel

and letter service prices guide and online UK parcel and letter price guide respectively.

Looking to end your package via DPD? We’ve also produced a guide to DPD Parcel Sizes.

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