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Packaging Guide: Large Letter

Large letter postal boxes can be highly beneficial for eCommerce businesses as they are cost effective, convenient for your customers and significantly reduces the risk of "failed to deliver" returns.

These boxes are perfect for shipping a wide range of items, from subscription boxes to items such as t-shirts/clothing, DVDs, magazines and small electrical items.

Large Letter Package Sizing

Our large letter postal boxes come in two sizes. These are both compatible with Royal Mail’s large letter guidelines and most UK letterboxes.

C5 Large Letter PIP Postal Box

9.02 x 6.26 x 0.63" (229 x 162 x 20mm) From 19.4p per box

C4 Large Letter PIP Postal Box

12.83 x 8.94 x 0.63" (324 x 229 x 20mm) From 27.8p per box

The dimensions given refer to the internal dimensions of the box and you can send packages that weigh up to 750g.

How to Pack and Secure Your Package

Our large letter postal boxes are made out of top-quality boards that are delivered flat-packed to reduce storage space before use. They can be easily assembled and are designed to be sturdy, ideal for going through the letterbox.

To Assemble and Pack:

  • Start by laying the box in front of you
  • For each indentation, fold the cardboard inwards, then you’re ready to pack
  • Place the product flat in the box
  • If the product does not fill the whole box we recommend filling the excess area with eco-friendly padding to protect your product
  • Once you have closed the box, secure it by taping around the edges of the lid

Simple as that!

Key Benefits

  • Cost effective
  • Reduces excess packaging
  • Convenience for your customer
  • Plastic free and 100% recyclable
  • Made in Britain

Cost to Send Large Letter Postal Boxes

  • 100g =£1.06
  • 250g = £1.50
  • 750g = £2.72

Our boxes come in packs of 50 and you can order as many as you like. Plus, there is a bulk buy discount when purchasing 600 or more boxes.

Thousands of boxes supplied to clients throughout the UK

Katie Barker
Katie Barker

Good Sturdy Boxes We have been using Boxed Up for a few years now, and is an integral part of us meeting our customers' expectations. They offer a friendly and professional service. The only negative we have is that their new website has been 'coming s


The one of the best box supplier in the UK I have ordered boxes from Boxed Up many times. They have great prices, very quick response time, next day delivery. What else can I say: The one of the best box supplier in the UK, Thank you

Kevin Mcgrath
Kevin Mcgrath

I ordered 25 Boxes from Boxed Up Packaging . They acknowledged the order and kept me informed as the order was being processed and I got notifications from the delivery company at each stage. What a fantastic system. This is how business should be done. I