cardboard postal boxes UK

cardboard postal boxes UK businesses use are corrugated boxes sized for letters and parcels sent through the UK postal network, protecting goods in transit while keeping postage predictable. Custom Postal Boxes manufactures cardboard postal boxes UK wide in sizes and print matched to your products, with low minimum orders and free UK delivery.

Choosing cardboard postal boxes UK sizes with confidence

Postage in the UK is set by the size and weight of the finished parcel, so the box should hug the product rather than dwarf it. Royal Mail large letter format allows up to 35.3 cm by 25 cm by 2.5 cm and 750 g, while the small parcel format allows up to 45 cm by 35 cm by 16 cm and 2 kg. A box designed just inside the band you need avoids paying for the next band up on every order.

Start by measuring the product at its widest points, then add room for protective wrap. Flat items such as books, prints and garments often suit letterbox friendly formats, while boxed goods, footwear and sets need parcel formats. The Royal Mail Tracked 24 page lists the limits for each format and is worth checking before you fix a box size.

Board grades explained simply

Single wall corrugated board suits most light and medium weight goods and keeps the pack light. Double wall board adds a second fluted layer for heavier or more fragile contents and stacks better in storage and transit. Kraft board gives a natural brown finish, and white board gives a cleaner base for bright print.

When to choose double wall

Choose double wall when the contents are heavy for their size, valuable, or likely to be stacked under other parcels. Our double wall shipping boxes show the stronger construction, while single wall corrugated boxes cover everyday posting needs.

Popular formats across the range

Letterbox formats are popular with subscription brands and sellers of flat goods because the parcel can be delivered without anyone waiting in. Standard parcel boxes cover the bulk of ecommerce orders, from cosmetics and candles to clothing and small electronics. For flat documents and artwork, large letter postal boxes keep contents flat and within the large letter band when packed carefully.

Smaller orders are covered by small postage boxes, and the full size led range sits under postal boxes by size. Print can be added inside and out, turning a protective box into the first moment of your brand the customer touches.

Packing well inside the box

Good packing is simple. Place the heaviest item at the base, fill voids so nothing can shift, and close the box so the flaps meet without bulging. A bulge of a few millimetres can push a parcel into a higher postage band, so test one finished pack with a tape measure and scales before a full run.

Ordering from a UK manufacturer

Custom Postal Boxes is a project of Vertex Packaging, based in Wolverhampton, and boxes are manufactured in house. That means sizes can be made to your product rather than forcing your product into a stock size. Design support is free, delivery across the UK is free and pricing depends on size, material and quantity. Send your product dimensions and quantities through the contact page for a quote and the team will recommend a board and format that protect the contents and respect your postage band.

FAQs about cardboard postal boxes UK

What is the largest box that still counts as a small parcel?

Royal Mail small parcel format allows up to 45 cm by 35 cm by 16 cm and 2 kg in total. Measure the finished packed box at its widest points, including any bulge, and weigh it with all packaging and labels included.

Should I choose single wall or double wall board?

Single wall board suits most light and medium weight products and keeps postage weight down. Double wall board is the safer choice for heavy, fragile or valuable contents, or where parcels will be stacked in transit or storage.

Can postal boxes be printed with my branding?

Yes. Boxes can be printed outside, inside or both, with your logo, colours and handling messages. Inside print is popular for subscription and gift brands because it rewards the customer at the moment of opening.

How do I get a price for cardboard postal boxes UK?

Pricing depends on size, material and quantity, so ordering works by quote. Share your product size, board preference and quantity through the contact page and the team will respond with a quote, free design support and free UK delivery.