How Letterbox Boxes Cut Shipping Costs for Online Retailers
Save significantly on every shipment by fitting products into letterbox-sized packaging.
The cost savings
The price difference between Royal Mail large letter (up to 25mm thick) and small parcel rates is substantial. For businesses shipping hundreds or thousands of items per month, switching eligible products to letterbox packaging delivers immediate, significant savings.
Quick answer
Letterbox boxes save £2-3+ per item by qualifying for Royal Mail large letter rates instead of small parcel. For a business shipping 500 items monthly, that is £1,000-1,500 saved per month. The box itself costs 20-50p, but the postage saving dwarfs this. Any product that fits within 353mm x 250mm x 25mm and under 750g is a candidate for letterbox packaging.
Rate comparison
The rate difference is the biggest single cost saving available through packaging optimisation.
Under 100g is cheapest. Each weight band up to 750g costs a little more.
Even non-Royal Mail carriers charge less for thinner, lighter packages.
Products that fit
Letterbox-friendly products0 / 6 checked
Size rules: Royal Mail letterbox rules or sizing guide.
Making the switch
Audit your product range for items under 25mm thick. Order letterbox box samples, test-pack your products, and verify the packed box fits through a standard UK letterbox. Calculate the per-item postage saving to build the business case. Start with your highest-volume products for the biggest immediate impact.
Start saving with letterbox boxes
ProcuraPack letterbox boxes designed to fit Royal Mail large letter limits for maximum savings.
Browse letterbox boxesFrequently asked questions
£2-3+ per item by qualifying for large letter rates (from 93p) instead of small parcel (from £3.35).
Maximum 353mm x 250mm x 25mm thick and under 750g for Royal Mail large letter rates.
Jewellery, phone cases, cosmetics, stationery, thin books, seeds, and other items under 25mm thick.
Yes, most couriers charge less for smaller, thinner packages even outside Royal Mail pricing.
750g for Royal Mail large letter. Each weight band within large letter has a different price.
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 →
