letterbox friendly packaging

For slim products, letterbox friendly packaging is designed to pass through a standard UK letterbox, so an order can be delivered safely even when nobody is at home. Custom Postal Boxes makes these slim boxes in Wolverhampton to Royal Mail large letter limits, with custom print, low minimum order quantities, free design support and free UK delivery. Fewer missed deliveries means fewer rearranged drops, less contact from customers and a better first impression.

How letterbox friendly packaging works in practice

The key limit is thickness. Royal Mail large letter items can measure up to 353 mm long, 250 mm wide and 25 mm thick, and weigh up to 750 g, as set out in the Royal Mail size and weight guidance. A box made just inside those limits, including its board and any bulge from contents, can travel as a large letter and pass through most letterboxes. Our letterbox postal boxes are built to that discipline, with low profiles that still feel rigid in the hand.

Products that suit letterbox delivery

Flat and slim goods suit this format best, including books, documents, artwork prints, clothing in a single layer, cosmetics, phone accessories, craft kits and greeting card or stationery orders. The product should sit flat without forcing the lid up, because a domed lid can push the parcel over the thickness limit. If your range includes both slim and bulky items, run two packaging formats side by side rather than forcing everything into the slim box and risking damage or a higher postage band.

Testing your box against the limit

Pack a real order, seal the box as a customer would receive it, then measure all three dimensions and weigh the complete parcel. Check the sealed box slides through a letterbox sized opening without force, and repeat the test with your bulkiest allowed contents. Labels, tape and outer wrap all add a little thickness, so include them in the test. This simple check, done once at design stage, prevents a whole print run of boxes that quietly miss the large letter limit in daily use.

Choosing materials and sizes for letterbox friendly packaging

Slim boxes are usually made from sturdy corrugated or solid board that resists bending, because a letterbox parcel may be pushed, flexed and dropped onto a hard floor. Our large letter postal boxes and A5 postal boxes cover common document and product sizes, while C4 postal boxes suit A4 contents. Keep the internal layout flat, place fragile items away from the edges and use a thin insert or board backed sleeve where extra stiffness will help the contents survive the drop through the door.

Print and information on a slim box

A slim box has less surface area, so keep print bold and brief. Your logo, a short line about the contents and clear handling wording are usually enough, with detailed guidance moved inside on a card. Branding still matters, because a letterbox parcel is often the first thing a customer sees on arriving home. Colour on the lid makes the parcel recognisable on the doormat and in photographs, while a plain underside keeps the design cost sensible if your budget is tight.

Print, packing and ordering advice

Letterbox delivery also changes the customer experience after dispatch. There is no card left for a missed delivery and no trip to a collection point for most orders, which suits subscriptions and repeat purchases especially well. When you brief a design, talk to us through our contact page about your product thickness and weight, and we will size the box to suit. Pricing depends on size, material and quantity, with free design support and free UK delivery included. Low minimum orders let you trial letterbox delivery on one product line before extending it across your shop.

FAQs about letterbox friendly packaging

What size counts as letterbox friendly packaging?

As a guide, Royal Mail large letter limits are 353 mm by 250 mm by 25 mm and up to 750 g, and a parcel within those limits will pass through most standard letterboxes. Always measure the sealed, filled box, including labels and tape.

What products can be sent through a letterbox?

Slim and flat products suit this format, such as books, documents, prints, stationery, flat packed clothing, cosmetics and small accessories. Bulky or fragile items that need thick cushioning are better sent as a small parcel.

Will a letterbox parcel be damaged by the drop through the door?

A well made slim box in sturdy board protects contents against the short drop onto a mat or floor. Keep fragile items away from the edges, hold them still with an insert and avoid overfilling, which weakens the structure.

Can letterbox friendly packaging be printed with my branding?

Yes. Lids can carry your logo, colours and a short message, and inside print or an insert card can carry more detail. Custom Postal Boxes includes free design support to help you use the smaller surface well.

How do I order letterbox friendly boxes?

Send your product dimensions and packed weight through our contact page and ask for a quote. Pricing depends on size, material and quantity, orders can start at low minimum quantities and UK delivery is free.