Category
Postal Boxes
Quick answer
Die-cut mailing boxes and PiP boxes for ecommerce despatch.
Postal boxes are the workhorse of any ecommerce despatch operation. Our range covers Royal Mail Large Letter (PiP) boxes, die-cut mailer boxes and standard single-wall cartons — sized to protect products in transit while keeping postage costs down. Whether you send a handful of orders a week or thousands, buying the right box size reduces void fill, damage and returns.
Best for
- Ecommerce order despatch
- Posting at Royal Mail Large Letter (PiP) rates
- Small, rigid or fragile items
- Branded unboxing (custom printed)
Common sizes & specs
A quick reference — exact spec is on each product and its spec sheet.
| PiP / Large Letter | Within 353 × 250 × 25mm to post as Large Letter |
|---|---|
| Small parcel mailers | Approx. 160–250mm, single-wall |
| Board grade | Single-wall kraft, widely recyclable |
| Closure | Tuck lid or self-lock base |
What to check before ordering
- Internal vs external dimensions — order to the product size, not the box size
- Depth against the 25mm Large Letter limit if posting PiP
- Whether a self-lock base would save you tape
- Recycled content / spec sheet if you make packaging claims
Postal Boxes products
3 products
PiP Large Letter Postal Box — A5
Royal Mail Large Letter box, folds flat, 25mm deep.
Single-Wall Mailer Box — Medium
Die-cut ecommerce mailer, easy fold, self-lock base.
Custom Printed Mailer Box
Branded mailer boxes printed to your artwork.
Buying postal boxes in volume?
Boxes get materially cheaper per unit by the pallet. If you're posting steady volumes, a bulk quote or trade account beats buying in small packs — and unlocks custom sizes and printed board.
Stocked, or sourced to order
We hold the fast-moving lines and source the rest through our UK supplier network — so you get one honest point of contact whether an item is on the shelf or made to order. We don't claim stock or delivery speed we can't meet.
Stocked lines
Core products we hold and despatch in listed pack sizes. Buy online at trade pricing.
Supplier network
Custom sizes, printed and specialist lines sourced to order. Priced per order, with a lead time confirmed up front.
New lines
Products being added to the range. Leave your email and we'll tell you the moment they land.
Specs, explained
- PiP (Pricing in Proportion)(Pricing in Proportion, PiP format, Royal Mail size-based pricing)
- Royal Mail's Pricing in Proportion system, where postage is set by an item's size and thickness as well as its weight. It sorts mail into format bands such as Letter, Large Letter and Small Parcel. More
- Royal Mail Large Letter(Large Letter format, LL)
- A Royal Mail PiP format for flat items up to 353 x 250 x 25mm and 750g. Staying within these limits keeps postage cheaper than Small Parcel rates. More
- Single-wall cardboard(Single wall board, Single-wall corrugated)
- Corrugated board made from one fluted layer sandwiched between two flat liners. It is the everyday choice for lightweight postal boxes and cartons. More
- Double-wall cardboard(Double wall board, Twin-wall corrugated)
- Corrugated board with two fluted layers and three liners, giving extra strength and cushioning. It is used for heavy, fragile or stacked shipments and moving boxes. More
Common buyer questions
What packaging do I need for ecommerce orders?
A box or mailing bag sized to the product, void fill or bubble wrap so nothing moves, plus tape and a courier label. Right-sizing keeps postage and damage down.
Which boxes fit Royal Mail Large Letter?
Boxes within 353 × 250 × 25mm post as a Large Letter. Our PiP postal boxes are cut to sit inside those limits so you pay the cheaper rate.
What is the best void fill for fragile items?
Pair cushioning (bubble wrap) around the item with void fill (kraft paper or air cushions) to stop movement. Fill any gap larger than about 3cm.
Poly or paper mailing bags — which should I use?
Poly mailers are waterproof, lightest and cheapest; paper mailers are kerbside recyclable with a premium feel but less water resistance.
Guides for postal boxes
Buying regularly?
Set up trade & repeat supply
If packaging is a running cost, a trade account keeps your regular lines on consistent pricing and makes reordering quick — with bulk quotes whenever volumes spike.
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Regular orders
Reorder your usual lines quickly, at consistent pricing.
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Bulk pricing
Case and pallet quantities priced to your volume.
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Custom quotes
Bespoke sizes and printed packaging, sourced to order.
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Trade account
One named contact who knows your account and products.
Postal Boxes — FAQs
What size postal box do I need for Royal Mail Large Letter?
Are your postal boxes made from recycled cardboard?
Can I order postal boxes in bulk with custom sizes?
Related categories
Popular buyer searches
Buying in volume? Get trade pricing.
Tell us what you need — sizes, quantities and how often. We'll send pricing and lead time, and source anything we don't stock through our supplier network.
