Grey Mailing Bags 9×12" (229×305 mm) – the smart A4-friendly choice for daily post

Grey mailing bags 9×12" (229×305 mm) are a top pick for UK sellers who send A4 items and small soft goods every day. This size fits A4 with room for padding or a folded garment, while keeping weight low. Made from tough 60-micron LDPE, these self-seal postal bags close in seconds, are water-resistant for wet weather, and the opaque grey film protects privacy from warehouse to doorstep.

Why this 9×12" size works so well

It’s compact, neat, and cost-effective. 9×12" is larger than A4 (210×297 mm), so you can slide in documents, brochures, and slim boxes without forcing the seal. It is also ideal for single T-shirts, kids’ clothing, light accessories, and beauty items in retail cartons. The footprint stacks cleanly in mail sacks and totes, which helps keep your packing area tidy and your dispatch fast.

Who it’s for

• Apparel & merch: single T-shirt, thin jumper, gym top, headwear, scarf, socks, small bundles.
• Beauty & wellness: boxed skincare, cosmetics palettes, hair accessories, nail kits.
• Stationery & print: A4 brochures, photo books, documents in wallets, diaries, planners.
• Craft & hobby: small fabric cuts, patterns, kits, components in inner sleeves.
• Marketplace sellers: quick, tidy packaging for high-turnover A4 orders.

Fit & packing guidance

• Best fit: A4 documents in a wallet, single T-shirt, thin jumper, boxed cosmetics, diaries, planners.
• If it feels tight: step up to 10×14" for thicker books or padded clothing.
• If it feels roomy: use a simple inner sleeve or fold once for a flatter parcel.
• Corner care: round or pad the corners of inner boxes to reduce punctures.
• Press out air: squeeze air before sealing so labels sit flat and postage stays low.

Key benefits

• Self-seal strip: fast, tamper-evident close for busy benches.
• 60-micron film: helps resist scuffs, splits and rough handling.
• Water-resistant: protection against rain and splashes in transit.
• Opaque grey: clean, professional look and contents privacy.
• Lightweight: reduces parcel weight vs small cartons.
• Recyclable LDPE: remove the glue strip before recycling.

Specifications

Strength, protection and a clean finish

The 60-micron film gives real-world toughness without adding bulk. It helps resist punctures from corners and keeps its shape through conveyors and cage moves. The self-seal strip bonds fast, so your team can pack and label with fewer pauses. The opaque grey finish maintains a tidy brand image and hides contents for a safer delivery experience. The water-resistant layer adds a simple buffer against showers and splashes.

Eco & recycling

These bags are LDPE and are recyclable in many UK schemes. Please remove the adhesive strip before recycling to help processing. If you need recycled-content or paper alternatives for certain orders, explore the full Mailing Bags collection for more options.

Size comparison (pick the best fit for each order)

If you often ship mixed sizes, keep both 10×14" and 9×12" on your bench so staff can choose the best fit. For bulkier items, move up again to 12×16".

Packing tips to save time and reduce damages

• Use a light inner sleeve for dusty or powder-prone items.
• Fold garments flat; avoid hard folds that create sharp corners.
• Apply labels on a smooth area and press firmly for reliable scanning.
• For returns paperwork, use a clear document wallet outside the bag.

FAQs

Does 9×12" fit A4?

Yes. It is larger than A4, so there’s room for a wallet, sleeve or light padding.

Are these bags waterproof?

They are water-resistant and help protect against rain and splashes. For very wet routes, add an inner sleeve.

Are they recyclable?

Yes. They are LDPE and recyclable in many UK schemes. Remove the glue strip first.

Do you sell bulk packs?

Yes. Larger pack sizes reduce your cost per bag. Choose a mix of sizes to match your order profile.

Build a complete packing setup

Team these grey mailing bags 9×12" with packaging tape for inner boxes, document wallets for paperwork, and cardboard boxes when rigid protection is needed. For more colours and sizes, visit the Mailing Bags collection.