Letterbox Boxes

Our Letterbox Boxes (Pricing in Proportion Large Letter Postal Boxes) are expertly designed for the UK market, enabling cost-effective, hassle-free delivery of small to medium-sized items directly through standard UK letterboxes—eliminating the need for redelivery attempts or collection from depots.

These slim, rigid boxes comply with Royal Mail's Large Letter specifications (maximum dimensions approximately 353mm × 250mm × 25mm external, with a weight limit of up to 750g), ensuring they qualify for significantly lower postage rates compared to standard parcels. Their low-profile construction (typically 19–22mm internal height, often around 20mm) guarantees reliable passage through most domestic and commercial letterbox slots (designed for the 25mm Royal Mail large letter slot), making them a favourite for e-commerce, direct-to-consumer retail, subscription services, and small business fulfilment across the UK.

Crafted from high-quality single-wall corrugated cardboard, these boxes provide sturdy protection against bending, crushing, minor impacts, and everyday postal handling while remaining lightweight to keep shipping costs down.

Key features and benefits include:

• Royal Mail Large Letter Compliance — Precisely sized to fit within PIP guidelines (e.g., popular formats: C6 ~160×110×20mm, C5/A5 ~220×160×20mm, DL ~220×110×20mm, C4/A4 ~320×230×20mm, Mini ~101×101×20mm, and maximum ~345×242×21mm), qualifying for Large Letter postage bands and avoiding parcel surcharges.
• Letterbox-Friendly Design — Slim depth ensures easy insertion through standard UK letterboxes, delivering convenience for customers (no missed deliveries) and reducing carrier costs/returns for senders.
• Durable Protection — Robust corrugated construction offers excellent rigidity and puncture resistance, safeguarding contents such as cosmetics, jewellery, books, stationery, small electronics, apparel, accessories, documents, gifts, nutraceuticals, or promotional items during sorting, transit, and doorstep handling.
• Lightweight Efficiency — Minimal added weight helps maximise the 750g limit and reduces postage fees on Royal Mail services (e.g., 1st/2nd Class Large Letter, Tracked, or Signed For options) as well as compatible couriers.
• Quick & Secure Assembly — Supplied flat-packed for space-saving storage; easy-fold designs with pre-scored lines; many features peel-and-seal adhesive strips (self-adhesive/tamper-evident) for fast, secure closure without extra tape—ideal for high-volume packing.
• Professional Presentation — Available in clean natural kraft brown (eco-rustic appeal). Smooth surfaces support high-quality direct printing, custom logos, thank-you notes, or adhesive labels, enhancing unboxing experiences and brand perception.