Bubble Envelopes
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Layflat Tubing Heavy duty
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If you regularly send items in the post, one of the most common questions is: which size padded envelope do I actually need? Whether you’re looking for small jiffy bags for jewellery, A5 padded envelopes for documents, large padded mailers for clothing, or anything in between — this guide covers everything.
What is a padded envelope?
A padded envelope — also called a bubble mailer, bubble envelope, jiffy bag, or padded mailer — is a postal bag with an inner lining that protects contents during transit. The most common type uses bubble film lining bonded to a kraft paper outer. These are lightweight, cheap to post, and protect against scuffs, drops and minor impacts.
The terms “jiffy bag”, “bubble mailer”, “padded envelope” and “bubble envelope” all refer to the same category of product. Jiffy is simply one brand name — like how people say “hoover” for vacuum cleaner.
Standard padded envelope sizes in the UK
Padded envelopes in the UK use a numbered size system. Here is what fits in each size, using Arofol sizing as the reference (one of the most widely used brands for bubble-lined mailers in the UK):
Size 1/A — 100 × 165mm (small jiffy bag size) The smallest padded envelope size available. Perfect for jewellery, USB drives, memory cards, gift cards, and small accessories. Fits within Royal Mail large letter dimensions when not overfilled.
Size 2/B — 120 × 215mm Slightly wider and taller. Good for small cosmetics, folded paperwork, single CDs, and phone accessories.
Size 3/C — 150 × 215mm (A5 padded envelope) One of the most popular sizes. Fits a single DVD, slim paperback, folded A5 document, and most small boxed products.
Size 4/D — 180 × 265mm (A5 jiffy bag size) Fits A5 documents flat, small clothing items folded, accessories, and small electronics. Equivalent to what many people search for as an “A5 jiffy bag”.
Size 5/E — 220 × 265mm A step up — fits small tablets, medium clothing, small gifts, and paperback books comfortably.
Size 6/F — 220 × 340mm (A4 padded envelope) One of the most popular sizes for business use. Fits A4 documents flat, brochures, clothing, and small boxed goods. This is what most people are looking for when searching for “A4 jiffy bags”.
Size 7/G — 230 × 340mm Slightly wider than 6/F. Fits hardback books, A4 ring binders, and bulkier clothing.
Size 8/H — 270 × 360mm (large jiffy bag) A large padded envelope suitable for multiple books, large folders, binders, and thicker items.
Size 9/I — 300 × 445mm (extra large padded envelope) Fits catalogues, large flat items, A3 paper folded in half, and larger boxed goods.
Size 10/K — 350 × 470mm (extra large bubble mailer) The largest standard bubble mailer size. Suitable for artwork, large books, A3 documents, and bulky flat items.
White or brown — which should I choose?
Both white and brown padded envelopes offer identical protection. The choice is mainly about presentation. Brown (kraft) envelopes have a natural, eco-friendly appearance — they’re popular with businesses who want a sustainable-looking package. White envelopes look cleaner and more premium, making them popular for retail and gifting businesses where unboxing presentation matters.
Both versions at Cloud Packaging are FSC-certified, made with 70% recycled materials, and fully recyclable.
Small padded envelopes — which size for Royal Mail large letter?
For Royal Mail large letter format (max 353 × 250mm, up to 25mm thick), sizes 1/A through 5/E all fit comfortably when not overfilled. Always check the thickness of your filled envelope — overfilling is the most common reason a large letter gets reclassified as a small parcel, which significantly increases the postage cost.
Buying padded envelopes in bulk
If you’re an ecommerce seller, fulfilment centre, or business dispatching regular orders, buying padded envelopes in bulk packs makes a significant difference to your cost per unit. At Cloud Packaging, pricing reduces from 4 packs and drops further at 8, 16, 25+ packs and full pallet quantities. Free next working day delivery is available across the UK mainland on orders over £30 — including the North West, Lancashire, Yorkshire, and all major cities.
