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Understanding Royal Mail Parcel Sizes

For those smaller ecommerce businesses and hobbyist who ship out their creations through the post, finding the right sized box can be crucial. Not only to ensure that your products arrive to the customer undamaged but that it fits within certain shipping criteria.

As most of you know, the main UK postal system Royal Mail updated their shipping sizing categories and corresponding pay structures. Over 2013 and 2014 they have changed their ‘pricing in proportion’ policy, abandoning its previous ‘packet’ category, to be replaced with two new bands called ‘small parcel’ and medium parcel’.The various changes Royal Mail have made in perfecting the various sizing price structures is to presumably remain in line with the growing online shopping trend.



As a manufacturer these sizes are important to consider, in order for us to create stock boxes which our customers require in order to ship their products within the certain category restrictions.

At present the current category information are as follows;

LARGE LETTER – 353mm x 250mm x20.5mm (750g weight)

SMALL PARCEL – 450mm x 350mm x 160mm (2kg weight)

MEDIUM PARCEL – 610mm x 460mm x 460mm (20kg weight)

Unless you want to keep a tape measure to hand and buy a new box for every different type of box you send out, which can become quite costly. It is beneficial to get your boxes from a trusted supplier who can guarantee that, as long as you remain within the weight restrictions, you can be confident which category your parcel will fall into.

A parcel need only go a few millimetres over the maximum to up your costs considerably. If you’re dispatching twenty 2kg parcels each working day on a 1st class service, using ‘medium parcel’ packaging instead of ‘small parcel’ could cost you an extra £69 a day, or £345 each week.

You can get a plastic guide from the Post Office – if your parcel passes through the relevant slot, you’ll know that it is the right size for that category. But that could be quite a long-winded exercise to do for every single box.

Alternatively you can feel at ease in the knowledge that our following stock box styles fall within the following categories;

LARGE LETTER:
PIP(C5)PIP(C4)

SMALL PARCEL:
4x4x45x5x2.55x5x56x4x36x4x46x5x46x6x67x5x2.57x5x5
8x6x48x6x69x6x39x6x69x7x310x10x612x7x312x9x2
12x9x412x9x617x13x317x13x6

MEDIUM PARCEL:
7x7x78x8x810x10x1012x9x918x12x12