What Are Letterbox Boxes and How Do They Work?
Everything you need to know about letterbox boxes: what they are, how they work, and why they matter.
What are letterbox boxes?
Letterbox boxes are thin, flat cardboard packaging designed to fit through a standard UK letterbox. They qualify for Royal Mail large letter postage rates, which are significantly cheaper than parcel rates. This makes them the packaging of choice for e-commerce businesses selling small, flat products.
Quick answer
Letterbox boxes are thin cardboard packages (under 25mm) designed to fit through a standard UK letterbox. They qualify for Royal Mail large letter rates (from 93p) instead of small parcel rates (from £3.35), saving £2-3 per shipment. Items are delivered without the customer needing to be home, eliminating missed deliveries. They are ideal for jewellery, cosmetics, phone cases, stationery, and subscription products.
How do they work?
Boxes store flat and assemble in seconds with tuck-flap or peel-and-seal closures.
The packing process is simple: insert product, close box, apply postage, post.
Designed to pass through the standard 250mm x 38mm letterbox opening.
The parcel lands on the doormat, guaranteeing first-time delivery.
Get started: complete guide or sizing guide.
Key benefits
Why businesses choose letterbox boxes0 / 5 checked
Who uses them?
Jewellery sellers, cosmetics brands, subscription box companies, stationery businesses, phone case retailers, seed companies, and any e-commerce business selling products under 25mm thick. If your products fit, the postage savings make letterbox boxes the obvious choice.
Browse letterbox boxes
Stock and custom letterbox boxes in every size from ProcuraPack.
Browse letterbox boxesFrequently asked questions
Thin cardboard packaging under 25mm thick, designed to fit through letterboxes and qualify for large letter postage.
£2-3 per item by qualifying for large letter rates (93p) vs small parcel (£3.35+).
Jewellery, phone cases, cosmetics, stationery, seeds, and any item under 25mm thick and 750g.
They are designed for the standard UK letterbox opening of approximately 250mm x 38mm.
Yes, fully recyclable through standard kerbside recycling collections.
Part of our guide
Product Guide: Letterbox Boxes
Expert guides on letterbox packaging, from sizing and Royal Mail rules to branding and sustainability.
Browse all guides →
