Jiffy Bags and Padded Envelopes: Sizes Chart and Uses

Padded envelopes are the quickest way to post small, light items without a box, and the usual mistake is picking the wrong size. Below is a full sizes chart, with notes on what fits where and when a different product does the job better. Pack Solution, a UK packaging supplier based in Manchester, wrote it.

The everyday word for these is jiffy bags, and bubble envelopes are the same thing under another name. The guide also covers fit checks for A5, A4 and A3 items, and what to use for flat documents, books and soft goods.

Quick Picks: Jiffy Bags and Padded Envelopes

Most small items suit White Bubble Padded Envelopes: self-seal envelopes with a bubble lining, in 10 sizes. Prints and documents that must stay flat go in board back envelopes, and books and boxed items that need depth go in capacity mailer envelopes.

Best for small items posted without a box

White Bubble Padded Envelopes

White self-seal envelopes with a bubble lining that cushions small items in the post, in 10 sizes.

• 10 sizes, EP1 A/000 to EP10 K/7
• 100 x 165mm up to 350 x 470mm
• Box of 100

From £8.00 ex VAT (£9.60 inc VAT)

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Best for flat prints and documents

Board Back Envelopes (Do Not Bend)

A stiff board back and a printed Do Not Bend warning keep photos, certificates and documents flat.

• C4, C5 and C6 sizes
• Boxes of 125 (C4, C5) or 250 (C6)
• Printed Do Not Bend warning

From £12.00 ex VAT (£14.40 inc VAT)

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Best for books and boxed items

Capacity Mailer Envelopes

Rigid board envelopes with an expanding 70mm gusset for extra depth and a flat finish.

• Four sizes, M1 to M4
• 70mm expanding gusset
• Boxes of 50

From £30.00 ex VAT (£36.00 inc VAT)

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Key Facts

• Our padded envelopes are white and self-seal, with a bubble lining.
• There are 10 sizes, EP1 A/000 (100 x 165mm) to EP10 K/7 (350 x 470mm), each in a box of 100.
• Measurements are width x length in millimetres.
• Board back envelopes come in C4, C5 and C6, with a printed Do Not Bend warning.
• Capacity mailers have a 70mm expanding gusset in four sizes, M1 to M4, in boxes of 50.
• Prices are shown excluding VAT and a VAT invoice comes with every order.

What Are Jiffy Bags and Padded Envelopes?

Jiffy bags are padded envelopes: paper-style postal envelopes with a bubble lining that cushions small items in the post. Jiffy is a brand name that has become the everyday word for the whole product, so you will also see padded bags and padded mailers used for the same thing.

Ours are sold as White Bubble Padded Envelopes. Each has a white outer for a printed label or handwritten address and a bubble lining against knocks. The self-seal strip is peel and press, so there is no tape or moistening. They are light, which helps keep postage costs down.

Online sellers, offices and crafters use them for jewellery, books, cosmetics and small electronics. The lining is a thin layer of bubbles with no rigid wall, so they suit light, small, robust items. Heavy items and sharp-cornered goods can push through the lining, and glass or ceramics are better in a box.

Padded Envelope Sizes Chart

Our padded envelopes run from EP1 A/000 at 100 x 165mm to EP10 K/7 at 350 x 470mm. The EP number sits alongside the traditional letter code, so you can match the size you already use.

Order by the box: the minimum is one box, the price per box drops as you order more, and a VAT invoice comes with every order, so you can keep several sizes in stock. Every size is white with a bubble lining and a self-seal flap, packed 100 to a box. Because the dimensions are the outside size, allow some extra room inside for the bubble lining and the flap.

Which Padded Envelope Size Do You Need?

Measure your item, add room for the lining and flap, then choose the smallest envelope that fits. An A5 item fits EP5, an A4 item fits EP7 or larger, and an A3 item needs the largest, EP10.

If you are after a jiffy bag large enough for clothing or a box set, EP8 H/5 to EP10 K/7 are the sizes to look at. For an A4 item, EP7 gives more side room than EP6 because the lining takes up space inside.

How to Pack a Padded Envelope

1. Measure the item at its widest, longest and thickest points, then pick a size from the chart.
2. Slide the item in so it sits flat, with the bubble lining on every side.
3. Peel the strip, fold the flap over and press along the seal. No tape or moistening is needed.
4. Squeeze the envelope gently. If the item moves freely, choose a smaller size or add a little paper inside.
5. Add a printed label or handwritten address to the white outer, and post it.

The white outer takes a printed label well, which speeds up packing when you send many parcels a day. A snug fit also looks neater and keeps the parcel compact, so keep several sizes on the bench.

Will It Go as a Large Letter or Small Parcel?

Postage class depends on the size, thickness and weight of the packed envelope. A flat, light padded envelope may fit the large letter format, while a thicker one is priced as a small parcel. Royal Mail sets the limits and they can change, so check them before you choose, and read our large letter and Royal Mail PIP guide for how sizing affects postage.

Pack the item first, then check the thickness of the filled envelope. The smallest envelope that closes cleanly keeps both size and weight down.

Padded Bubble Mailers or Bubble Pouches?

Padded bubble mailers are complete postal envelopes. Bubble pouches are open-ended bags made as inner protection, and a pouch goes inside a box, padded envelope or mailing bag before it is posted.

We sell bubble pouches in seven sizes, BP1 (100 x 135mm) to BP7 (380 x 425mm), boxed from 100 to 750. They suit glassware, ceramics, electronics and cosmetics that need an extra layer inside a larger parcel. BP3 (180 x 230mm) takes small bottles and an A5 item slides in flat, while BP5 and BP6 take A4 items and small framed prints. If you ship fragile products, our bubble wrap guide explains when a roll beats a pouch.

Best for inner protection inside a parcel

Bubble Pouches

Ready-made open-ended bags of bubble wrap that protect single items inside boxes and mailers.

• Seven sizes, BP1 to BP7
• BP1 (100 x 135mm) to BP7 (380 x 425mm)
• Boxed from 100 to 750

From £30.00 ex VAT (£36.00 inc VAT)

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Board Back Envelopes and Capacity Mailers

Use board back envelopes when contents must stay flat, and capacity mailers when the item is thick. Neither has the soft bubble lining of a padded envelope.

Board back envelopes have a stiff board back and a printed Do Not Bend warning, in C4 (324 x 229mm), C5 (229 x 162mm) and C6 (162 x 114mm). C4 takes A4 paper unfolded, C5 takes A5 prints and cards, and C6 takes postcard-sized items. C4 and C5 come in boxes of 125, and C6 in boxes of 250.

Capacity mailers are rigid board envelopes with an expanding 70mm gusset, which suits books and boxed products. The four sizes are M1 (219 x 155 x 70mm), M2 (250 x 165 x 70mm), M3 (285 x 205 x 70mm) and M4 (312 x 250 x 70mm), in boxes of 50. M1 takes an A5 item, and M4 takes an A4 item. Measure the thickness of the item as well as its length and width.

For a wider comparison with boxes, read padded envelopes vs postal boxes.

Padded Bags or Mailing Bags for Soft Goods?

For clothing and other soft goods, a mailing bag is usually the better fit than padded bags, because there is nothing fragile to cushion. Mailing bags are opaque polythene with a self-seal strip and a water resistant outer, so they protect against rain in transit.

The grey mailing bags come in 16 sizes, from 4 x 6" (100 x 150mm) to 34 x 42" (850 x 1050mm). The 9 x 12" (230 x 300mm) size takes an A4 document flat, and the 17 x 24" size and above suit bulky soft goods such as bedding and cushions. Smaller sizes come in packs of 100, larger sizes in packs of 50 or 25. Our mailing bag sizes guide goes through them in detail.

Best for clothing and soft goods

Grey Mailing Bags

Lightweight, opaque grey polythene bags with a self-seal strip and a water resistant outer.

• 16 sizes, 4 x 6" to 34 x 42"
• Self-seal adhesive strip
• Packs of 100, 50 or 25

From £2.90 ex VAT (£3.48 inc VAT)

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Padded Envelope Buying Checklist

• Measure the item at its widest, longest and thickest points.
• Allow room for the bubble lining and the flap.
• A5 items: EP5. A4 items: EP7 or larger. A3 items: EP10.
• Use board back envelopes if the contents must not bend.
• Choose capacity mailers for books and boxed items that need depth.
• Use mailing bags for clothing and soft goods.
• Put fragile glass or ceramics in a box, with bubble pouches inside if needed.
• Check Royal Mail size and weight limits for the packed envelope.

Choosing the Right Envelope: Wrap-Up

Pick the smallest padded envelope that closes cleanly around your item, and move to board backs, capacity mailers or mailing bags when the product calls for it. Orders placed by 2pm Monday to Friday are dispatched the same working day, and Royal Mail Tracked 48 is free with no minimum.

Browse the full envelopes collection for every size, or see the bags collection for mailing bags. Unused items can be returned within 30 days of delivery under the refund policy.

Frequently Asked Questions

What are Jiffy bags?

Jiffy bags are padded envelopes with a bubble lining that cushions small items in the post. Jiffy is a brand name that people use for the whole product. Ours are sold as White Bubble Padded Envelopes, with a self-seal flap and 10 sizes.

What size padded envelope fits A4?

An A4 sheet is 210 x 297mm, and the bubble lining takes up room inside. Choose EP7 G/4 (230 x 340mm) or larger for A4 items. EP6 F/3 (220 x 340mm) is also suitable for documents, but EP7 gives more side room.

Which padded envelope is a Jiffy bag large enough for clothing?

The bigger padded envelopes suit clothing and box sets: EP8 H/5 (270 x 360mm), EP9 J/6 (300 x 445mm) and EP10 K/7 (350 x 470mm). For soft goods like bedding, grey mailing bags in the larger sizes are a better fit.

What is the difference between padded bags, padded mailers and bubble mailers?

They are different names for the same product: a postal envelope lined with bubble cushioning. Padded envelopes, padded mailers and bubble envelopes all describe it. Padded bags can also mean a polythene mailing bag, which has no padding.

How many padded envelopes are in a box?

Each box holds 100 envelopes of one size. The minimum order is one box, and the price per box drops automatically as you order more boxes. Prices are shown excluding VAT and a VAT invoice comes with every order.

Can bubble pouches be posted on their own?

No. Bubble pouches are made as inner protection and have an open end. Put the pouch inside a box, padded envelope or mailing bag before you post it. For items posted without a box, choose a padded envelope.

Shop for This Job

• Envelopes
• Mailing & Polythene Bags

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