corrugated boxes

corrugated boxes are cartons made from corrugated board, where a fluted paper layer is bonded between flat liners to create a light but strong packaging material. They are the standard choice for posting, shipping and storing goods in the UK, and Custom Postal Boxes makes corrugated boxes to custom sizes with print, low minimum order quantities and free UK delivery.

What corrugated boxes are and how board is graded

Corrugated board looks simple, but its performance comes from geometry. The wavy flute holds the two liners apart, much as a beam gains strength from its depth, so the finished board resists bending and crushing far better than flat paperboard of the same weight. The trapped air also cushions contents against knocks and gives some insulation against temperature change during a short journey.

Board is described by its wall structure and its flute size. A larger flute gives more cushioning and stacking strength, while a smaller flute gives a smoother surface for print and suits smaller cartons. Liner papers include kraft, made from virgin pulp and valued for strength and print quality, and test liner, made from recycled fibre and often used for the inner face.

Single wall, double wall and triple wall compared

Single Wall Corrugated Boxes have one fluted layer and suit light to medium weight goods in everyday despatch and storage. Double Wall Shipping Boxes add a second flute and liner, giving a stiffer board for heavier products, fragile goods and pallet stacking. Triple wall board adds a third layer for very heavy or industrial loads and is less common in consumer parcels. Choosing more board than you need adds weight and cost, so match the grade to the load rather than buying the strongest option by default.

How to judge board quality when samples arrive

Squeeze the edge of the board between finger and thumb. It should feel firm and spring back rather than staying crushed. Look at the cut edge to check the flute is regular and well bonded, fold a carton up and check the corners sit square, then pack your product and test the finished parcel.

Choosing corrugated boxes for your products

Custom sizing matters because empty space is a cost twice over. You pay to ship air, and you pay for filler to stop the product moving into that space. A box made around your product reduces both costs and usually reduces damage, since a snug product cannot build up speed before it hits the wall of the box. Explore Corrugated Shipping Boxes and Cardboard Shipping Boxes for shipping led formats.

Print, finish and fittings that add real value

Printing your logo, handling guidance and returns information on the carton reduces the need for separate labels and paperwork. Fittings cut from corrugated board can separate bottles, protect screens or hold a product away from the box walls, and they can be recycled with the box afterwards.

Sustainability, postage and ordering corrugated boxes

Corrugated board is made with a high proportion of recycled fibre in the UK and is widely recycled after use, which is one reason it has stayed the default material for parcels. Using the right size box, avoiding unnecessary filler and keeping the pack to one material where you can all support that record. Businesses placing packaging on the market should also read the GOV.UK extended producer responsibility for packaging guidance to understand current reporting duties.

Size also drives postage. Royal Mail and other carriers price parcels by format and weight, so check your packed dimensions against the service you use and avoid a carton that is larger than the product needs. Pricing for custom boxes depends on size, material and quantity and is provided as a quote, with free design support included. Send your dimensions through our contact page and tell us how the goods travel, so the board grade in your quote reflects the real journey.

Storage and handling tips for corrugated cartons

Store cartons flat, dry and off the floor, away from doors where rain can reach them. Damp board loses a large part of its stacking strength, so a carton that has been wet should not be trusted with a heavy load.

FAQs about corrugated boxes

Key answers for anyone comparing board grades, sizes and styles for the first time.

What is the difference between cardboard and corrugated board?

Cardboard is a general word for thick paper based material. Corrugated board is a specific structure with a fluted layer bonded between flat liners, which makes it much stronger and more cushioning for its weight.

Which is stronger, single wall or double wall?

Double wall board is stronger. It has two fluted layers and an extra liner, so it resists crushing and stacking pressure better and suits heavier or fragile goods.

Can corrugated boxes be custom printed?

Yes. Corrugated boxes can be printed with logos, product information, handling guidance and full designs on the outside, and mailer styles can also be printed inside the lid.

Are corrugated boxes recyclable in the UK?

Yes. Corrugated cardboard is widely collected for recycling from homes and workplaces in the UK. Keep the board clean and dry, remove tape where practical and flatten the box.

How do I work out the box size I need?

Measure the product as it will be packed, including any wrap or fittings, and use those measurements as the internal size of the box.