Bubble Envelopes: Size Chart and Which Size Fits A5, A4 and A3

Bubble envelopes are the quickest way to post small, flat or lightly fragile items: drop the item in, peel the strip and press the flap down. Choosing the right size is where most orders go wrong, so this guide sets out every size we stock in millimetres, which one takes A5, A4 and A3, which ones go as a Royal Mail Large Letter, and when a bubble pouch, board back envelope or PIP box does the job better.

Our padded bubble envelopes come in 10 sizes, from EP1 A/000 (100 x 165mm) to EP10 K/7 (350 x 470mm), all white, all self-seal, and all packed 100 to a box. If you want the older Jiffy style codes explained in more depth, our jiffy bags and padded envelopes sizes guide covers them. This page sticks to sizes and A paper fits.

Quick picks: which bubble envelopes and mailers to order

Most online sellers need one or two envelope sizes for everyday orders, plus pouches for anything that rattles and a flat option for prints.

Best for posting small items, books and A4 documents

White Bubble Padded Envelopes

White self-seal envelopes with a bubble lining, in 10 sizes from EP1 to EP10.

• EP1 (100 x 165mm) to EP10 (350 x 470mm)
• Box of 100 per size
• Self-seal flap, no tape needed

From £8.00 ex VAT (£9.60 inc VAT)

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Best for wrapping single items inside a box or envelope

Bubble Pouches

Open-ended bubble wrap bags that slide over a product, so you skip cutting wrap off a roll.

• 7 sizes, BP1 (100 x 135mm) to BP7 (380 x 425mm)
• Boxes of 750 down to 100
• Fold or tape the open end

From £30.00 ex VAT (£36.00 inc VAT)

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Best for prints, photos and certificates that must stay flat

Board Back Envelopes (Do Not Bend)

A stiff board back and a printed Do Not Bend warning keep paper items flat in the post.

• C4, C5 and C6 sizes
• C4 and C5 in boxes of 125
• C6 in boxes of 250

From £12.00 ex VAT (£14.40 inc VAT)

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What bubble envelope sizes do you stock?

Every size carries an EP number and the older letter code, so you can match the size you already buy from another supplier. Measurements are width x length in millimetres, taken flat, before anything goes inside.

These are bubble lined envelopes, and the lining sits inside these measurements, so the usable space is a little smaller than the outside size. Measure your item, then add room for the lining on every side and for the flap at the top. If your item is close to the limit, step up one size. An envelope that closes flat seals properly, and one that is stretched round the item tends to split at the seams.

Choose your bubble envelope size

Which bubble envelope fits A5, A4 and A3?

A paper sizes are the easiest way to judge fit, because notebooks, prints, documents and many boxed products are made to them. A5 is 148 x 210mm, A4 is 210 x 297mm and A3 is 297 x 420mm.

A5 bubble envelopes. EP5 E/2 is the size to order. Its 220mm width leaves plenty of room round a 148mm wide A5 notebook, planner or set of cards, and the 265mm length clears the 210mm sheet with space for the flap. EP4 D/1 is 180mm wide, which suits a slim A5 booklet, though the lining makes it a snug fit for anything thicker.

A4 bubble envelopes. EP7 G/4 (230 x 340mm) is our usual answer. EP6 F/3 (220 x 340mm) also takes an A4 sheet, but EP7 gives you an extra 10mm of width, which matters once the lining is inside and the document is in a plastic wallet or has a few pages of thickness. If you post A4 paperwork that needs no cushioning, our guide to board back and capacity envelopes covers the flat options.

A3 bubble envelope. EP10 K/7 (350 x 470mm) has the most room and is the one to choose for A3 prints and posters posted flat. EP9 J/6 is 300mm wide, only 3mm more than an A3 sheet, so the lining makes it too tight for A3. A large bubble envelope like EP10 suits soft, flexible items well, and big bubble envelopes in general work best when the contents can flex a little. For a framed A3 print or anything that must not flex, a box gives better protection.

Which small bubble envelopes suit jewellery, cards and phone accessories?

The three smallest sizes cover most small, light orders. They are also the sizes that sellers on eBay, Etsy and Vinted go through fastest, so they are worth stocking in more than one box.

• EP1 A/000 (100 x 165mm). Tiny bubble mailers for rings, earrings, keys and memory cards. A small jewellery box usually fits here.
• EP2 B/00 (120 x 215mm). Longer and slightly wider, for necklaces in a pouch, bracelets, charging cables and small accessories.
• EP3 C/0 (150 x 215mm). Small bubble mailers for phone cases, screen protectors, lipsticks and greetings cards. An A6 card fits with room to spare.

For anything delicate, such as a glass bead bracelet or a phone lens, slip it into one of our small bubble pouches first. BP1 (100 x 135mm) and BP2 (130 x 180mm) are made for jewellery boxes, lipsticks and phone accessories, and a BP1 pouch sits inside an EP2 or EP3 envelope. That gives you two layers of bubble without wrapping anything by hand.

Which bubble envelope sizes go as a Royal Mail Large Letter?

Royal Mail charges by size and weight, and the Large Letter rate is lower than Small Parcel. A Large Letter can be up to 353 x 250 x 25mm and weigh up to 750g. Check Royal Mail for the current limits before you post, as they can change.

So a royal mail bubble envelope for Large Letter use means EP1 to EP7. The footprint is the easy part. The thickness is what catches people out, because a filled envelope puffs up. Once the item is inside and the flap is sealed, check the thickness at the fattest point. A paperback or a phone case usually passes. A boxed gift or a folded jumper often does not.

EP8 H/5, EP9 J/6 and EP10 K/7 are extra large bubble mailers for clothing, box sets and A3 prints, and they always go at the Small Parcel rate or above. That is fine when the item needs the room, but if you can fit the order into EP7 instead, the postage is usually lower.

These are ordinary post office bubble envelopes: seal the flap, add stamps or a printed label, and hand them over the counter or to a courier such as Royal Mail, Evri, DPD or InPost.

Bubble envelopes, bubble pouches, board back envelopes or PIP boxes?

All four are flat, light and sold in bulk, but each one does a different job. Picking the right one saves postage and damaged items.

Bubble envelopes suit books, cosmetics, small electronics, clothing and documents that need some cushioning. They bend, so they are not the right choice for photos or prints. Our comparison of padded envelopes vs postal boxes covers that trade in more detail.

Bubble pouches are open-ended bags of bubble wrap. They look like postage bubble bags, yet they are made as inner protection, so the pouch goes inside a box or padded envelope before it is posted. An air bubble bag like this is quicker than cutting and taping wrap from a roll, which is why these packaging bubble bags are popular at busy dispatch benches. If you need a bubble bag for packing several products a day, this is the faster route. Slide the product in, fold the open end over or seal it with tape, then pack it. BP3 (180 x 230mm) takes an A5 sheet flat, BP5 (280 x 375mm) and BP6 (305 x 425mm) take A4 items, and BP7 (380 x 425mm) is the extra large size for homeware and artwork.

Board back envelopes have a stiff board back and a printed Do Not Bend warning. C4 (324 x 229mm) takes A4 unfolded, C5 (229 x 162mm) takes A5 and 6 x 8 inch photos, and C6 (162 x 114mm) takes A6 postcards and 6 x 4 inch photos. Use them for prints, certificates and trading cards rather than anything that needs cushioning.

PIP large letter boxes are die cut cardboard boxes, 20mm deep, supplied flat in packs of 50. Mini (101 x 101 x 20mm) suits rings and badges, C6 (163 x 112 x 20mm) suits phone accessories, DL (218 x 108 x 20mm) suits pens and straps, C5 (229 x 159 x 20mm) takes A5 and C4 (325 x 225 x 20mm) takes A4. Our large letter boxes guide explains how to use them.

Best for small items that need more protection than an envelope

Royal Mail PIP Large Letter Boxes

Die cut cardboard boxes 20mm deep, supplied flat and folded up by hand.

• Mini, C6, DL, C5 and C4 sizes
• Every box is 20mm deep
• Packs of 50

From £5.00 ex VAT (£6.00 inc VAT)

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How do you pack bubble envelopes so items arrive safely?

1. Pick the size after measuring. Allow room for the lining and the flap. The item should slide in without forcing.
2. Add a pouch for anything fragile or loose. A small bubble pouch stops an item sliding about and adds a second layer of bubble.
3. Keep sharp corners away from the seams. Turn a boxed item so its flat face sits against the lining, not its corners against the edge.
4. Seal flat. Peel the strip and press the flap down along its full length. You do not need tape or water.
5. Label the flat face. The white outer takes a printed label or a handwritten address. Keep the label clear of the flap so it scans first time.

For books in particular, our guide on how to post books covers which sizes suit paperbacks and hardbacks.

How many bubble envelopes should you buy at once?

Every envelope size comes in a box of 100, and the price per box falls as you order more boxes, with each tier shown on the product page. Prices on the site are ex VAT, and every order comes with a VAT invoice.

A simple way to plan: count how many orders a week go in each size, then keep two to four weeks of stock. A seller posting 25 orders a week in EP3 gets through a box in about a month, so one box at a time is fine. A seller posting 25 a day in EP3 uses a box in four working days, so ordering five or more boxes at once brings the unit cost down and saves reordering every week.

Bubble bags for packaging and bubble mailer bags are easy to overstock, so start small. Most shops settle on two or three padded bubble mailers sizes and keep the rest as occasional orders. A common mix is EP2 or EP3 for small accessories, EP5 for A5 items and boxed gifts, and EP7 for A4 and books. Keep one box of bubble pouches alongside them for fragile items. BP1 comes 750 to a box and BP2 500 to a box, so a single box lasts a long time.

For bubble envelopes bulk orders beyond the tiers on the product page, call 0161 706 1246 or email sales@packsolution.co.uk. The same goes for bubble mailers bulk orders mixed across several sizes. Businesses that order regularly can apply for a trade account.

Ordering bubble envelope mailers from Pack Solution

Orders placed by 2pm Monday to Friday are dispatched from Manchester the same working day. Royal Mail Tracked 48 is free on every order with no minimum, and faster paid options are at checkout. Free click and collect from Unit 2, 50 Derby Street, Manchester M8 8HF is usually ready within 2 hours, and businesses close to Cheetham Hill can use our local van delivery.

The rest of our range of mailing bubble envelopes and flat mailers is in the envelopes collection, and mailing bags for clothing are in the bags collection. If you are not sure which size to pick, contact us with the item measurements and we will tell you.

Order white bubble envelopes

Frequently Asked Questions

What size bubble envelope do I need for A4?

EP7 G/4 (230 x 340mm). An A4 sheet is 210 x 297mm and the bubble lining takes up some of the inside, so the extra width of EP7 matters. EP6 F/3 (220 x 340mm) also takes A4 but is a closer fit.

What size bubble envelope fits A5?

EP5 E/2 (220 x 265mm). A5 is 148 x 210mm, so it slides in with room for the lining and the flap. For an A5 print that must stay flat, a C5 board back envelope is the better choice.

Can I post a bubble envelope as a Royal Mail Large Letter?

Yes, if it stays within the Large Letter limits of 353 x 250 x 25mm and 750g. EP1 to EP7 all fit that footprint when flat, so the thickness and weight of what you put inside decide the rate. Check Royal Mail for current limits before you post.

How many bubble envelopes are in a box?

100. Every size from EP1 to EP10 comes in a box of 100 envelopes of one size, and the price per box falls as you order more boxes.

Are bubble pouches the same as bubble envelopes?

No. Bubble pouches are open-ended bubble wrap bags with no seal, made as inner protection. Put the pouch inside a box or padded envelope before posting it.

Do you sell coloured bubble envelopes?

No. Our bubble padded envelopes are white. The white outer takes a printed label or a handwritten address.

Shop for This Job

• Envelopes
• Mailing & Polythene Bags

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