Custom Postal Boxes

Construction and Board

Most postal boxes are made from E-flute corrugated board, which is thin enough to keep a Large Letter box within its depth limit yet strong enough to protect the contents. B-flute is thicker and gives more crush resistance for heavier or fragile products in parcel sizes; the guide to board and card types compares the two. The outer liner can be brown kraft or white, depending on how you want the box to look.

The usual construction is a crash-lock or a tuck-front mailer. A tuck-front mailer closes with a front flap that tucks into the base, needs no tape and opens neatly. Adding a peel-and-seal adhesive strip and a tear strip makes it quick to close at the packing bench and easy for customers to open, which also works for returns if you add a second strip.

Ask for the board grade that matches your product rather than the heaviest available. A pair of socks does not need the crush strength of a box carrying a glass candle, and over-specifying the board adds cost and weight to every order. If you sell a mix of products, two or three box sizes in different grades often work better than one box for everything.

Printing for Parcels

A printed postal box makes the parcel recognisable on the doorstep. Even a single colour logo on kraft board gives a professional look, and full colour on white board brings photography and patterns to life, as the print and finish options compared page shows. Printing the inside of the box adds a reveal moment when the customer opens it, without drawing attention to the outside in transit, which some sellers prefer for valuable items.

Keep the address area clear if you print the top of the box, so labels can be stuck down without covering key parts of the design. A short line on the inside, such as a thank-you or a care note, is a simple touch customers notice.

Measuring for a Postal Box

Start with the product in whatever wrap it will be posted in, such as tissue, a sleeve or a pouch. Measure its length, width and height, then add a few millimetres of clearance, following the steps in the measuring guide. If you want to fit inside a postage band, work backwards from that band's outer limit, subtracting the board thickness on each side to find the maximum inside size.

If the product is fragile, allow room for a small insert or padding. For Large Letter boxes, remember that the depth limit includes the closed box, so very little space is available for padding; a snug fit and a stiff product wrap are usually the best protection.

Before ordering a large run, it is sensible to post a sample to yourself or a friend. Seeing how the box arrives, whether it fitted through the letterbox, how the corners held up and how easy it was to open tells you more than any measurement on paper. If you have a plain box of a similar size, use it for that trial run before the printed order goes ahead.

Sellers Who Use Custom Postal Boxes

Jewellery makers, sock and underwear brands, cosmetic and skincare sellers, print and art sellers, phone accessory brands, coffee and tea subscriptions, and small craft businesses all rely on postal boxes. Subscription box services in particular benefit from a box sized to Large Letter, because subscribers are often out at work when deliveries arrive.

Marketplace sellers on platforms such as Etsy, eBay and Amazon also use printed postal boxes to look different from sellers using plain packaging, and to encourage repeat orders direct from their own websites.

Small businesses that pack orders at a kitchen table benefit just as much as larger warehouses. A box that folds up in seconds, closes without tape and fits the product without padding saves time on every order, which matters when the person packing is also the person making the product, answering emails and running the shop.

Work Back From the Postage Band, Then Subtract the Board

Postal boxes are sized from the outside in. Decide which postage band you want to hit first, Large Letter at 353 x 250 x 25 mm or a small parcel, then subtract the board thickness to get the inside size, and only then check that your wrapped product fits with a few millimetres of clearance. Product first is how a box ends up 2 mm too deep for the letter rate. Weigh a packed order too, since the band has a weight limit as well as a size. Then pick E-flute for slim boxes and B-flute for heavier parcel sizes.

Tell us the product size, the postage band, the board and print you prefer and roughly how many boxes you use a month, and a custom quote follows by email within one working day, from £0.25 each with minimums set per job. The free design proof shows the box flat with print positioned. Production takes 4 to 7 working days after approval and the flat boxes reach UK mainland addresses on free tracked delivery in 2 to 3 working days. Sellers who ship a second, chunkier line often add retention boxes for fragile items in the same artwork.