Mailing bags packaging guide
What is a padded mailing bag?
Padded mailing bags are often refreed to as jiffy bags. Padded mailing bag is the name given to any kind of mailing envelope with some form of cushioning as a liner. They have a very strong pure kraft paper outer and a lining of macerated paper fibres.
Padded mailing bag remains the only truly eco-friendly postal bag as it is easily reusable and recyclable.
Why choose padded mailing bags?
Padded mailing bags are bubble lined bags that are designed for durability and ease of use, providing excellent protection for parcels. Made from high quality paper, they feature heat welded edges for improved burst resistance and a high slip coated interior for smooth, snag-free packing. Plus, with a secure peel and seal closure, there is no need for additional adhesives.
Padded mailing bag sizes
| Airkraft | Mailmiser | Internal size | External size | PIP | Suggested use |
|---|---|---|---|---|---|
| AK000 | MM000 | 90 x 145 mm | 120 x 160 mm | Large letter | A7 jewellery |
| AK00 | MM000 | 115 x 195 mm | 145 x 210 mm | Large letter | A6 floppy disks |
| AK0 | MM0 | 140 x 195 mm | 170 x 210 mm | Large letter | CDs |
| AK1 | MM1 | 170 x 245 mm | 200 x 260 mm | Large letter | A5, videos, DVDs |
| AK2 | MM2 | 205 x 245 mm | 235 x 260 mm | Large letter | Small gifts |
| AK3 | MM3 | 220 x 320 mm | 250 x 335 mm | Large letter | Desk diary |
| AK4 | MM4 | 240 x 320 mm | 270 x 335 mm | Packet | A4 brochures |
| AK5 | MM5 | 260 x 345 mm | 290 x 360 mm | Packet | Books, 2 DVDs |
| AK6 | MM6 | 290 x 445 mm | 320 x 460 mm | Packet | Shirts, clothes |
| AK7 | MM7 | 340 x 445 mm | 370 x 540 mm | Packet | A3 |
| Padded bags | Internal size | External size | PIP | Suggested use |
|---|---|---|---|---|
| PB00 | 105 x 229 mm | 120 x 254 mm | Large letter | A6, audio tapes |
| PB0 | 135 x 229 mm | 150 x 254 mm | Large letter | |
| PB1 | 165 x 280 mm | 180 x 305 mm | Large letter | A5, CDs, videos |
| PB2 | 195 x 280 mm | 210 x 305 mm | Large letter | |
| PB3 | 195 x 343 mm | 210 x 368 mm | Large letter | |
| PB4 | 225 x 343 mm | 241 x 368 mm | Large letter | A4 |
| PB5 | 245 x 381 mm | 260 x 406 mm | Packet | |
| PB6 | 295 x 458 mm | 310 x 483 mm | Packet | |
| PB7 | 341 x 483 mm | 356 x 508 mm | Packet | A3 |
| PB8 | 442 x 661 mm | 457 x 686 mm | Packet | A2 |
Royal Mail PIP guidelines
Our mailing bags comply with Royal Mail pricing in proportion guidelines. The following table shows Royal Mail pricing in proportion requirements, limitations and details for each option.
| PIP Size | Max length | Max width | Max depth | Max weight |
|---|---|---|---|---|
| Letter | 240 mm | 165 mm | 5 mm | 0.1 kg |
| Large letter | 353 mm | 250 mm | 25 mm | 0.75 kg |
| Small parcel | 450 mm | 350 mm | 160 mm | 2 kg |
| Medium parcel | 610 mm | 460 mm | 460 mm | 20 kg |
| Large parcel | 610 mm | 460 mm | 460 mm | 30 kg |
Rolls and postal tube shaped items
For rolls and postal tube shaped items, the length of the item plus twice the diameter must not exceed 104 cm. The greatest dimension (either the length or diameter) must be no greater than 90 cm.
Padded envelope size conversion chart
| BLB size | Internal dimensions | External dimensions | Postal size | Arofol | Jiffy | Featherpost | Mail lite |
|---|---|---|---|---|---|---|---|
| 000 | 100 x 165 mm | 120 x 175 mm | Letter | 1 | JL000 | A | A/000 |
| 00 | 120 x 215 mm | 140 x 225 mm | Letter | 2 | JL00 | B | B/00 |
| 0 | 150 x 215 mm | 170 x 225 mm | Large Letter | 3 | JL0 | C | C/0 |
| 1 | 180 x 265 mm | 200 x 275 mm | Large Letter | 4 | JL1 | D | D/1 |
| 2 | 220 x 265 mm | 240 x 275 mm | Large Letter | 5 | JL2 | E | E/2 |
| 3 | 220 x 340 mm | 240 x 350 mm | Large Letter | 6 | JL3 | F | F/3 |
| 4 | 225 x 330 mm | 250 x 350 mm | Large Letter | 7 | JL4 | G | G/4 |
| 5 | 270 x 360 mm | 290 x 370 mm | Small Parcel | 8 | JL5 | H | H/5 |
| 6 | 300 x 445 mm | 320 x 455 mm | Medium Parcel | 9 | JL6 | J | J/6 |
| 7 | 350 x 470 mm | 370 x 480 mm | Medium Parcel | 10 | JL7 | K | K/7 |
| 8 | 440 x 670 mm | 460 x 680 mm | Medium Parcel | 12 | JL8 | L | L/8 |
Royal Mail size, weight guide
Reduce postal costs by ensuring your parcels are as compact as possible. Oversized packaging can result in paying up to 40% more. Choosing the right packaging is crucial for keeping postage costs low.
| Size | |
|---|---|
| Letter | Ideal for small documents or items. Tip: Fold A4 documents to fit C5 envelopes to qualify as a standard letter pricing. |
| Large letter | Suitable for smaller items that do not require a box. |
| Small parcel | Best for items weighing 1 to 2 kg. |
| Medium parcel | Weight range 2 to 20 kg. |
| Large parcel | Exceeds 610 x 460 x 460 mm or weighs 20 kg plus. |
Mailing bag questions
How do I work out if my box will fit in the mailing bag?
Take a soft tape measure and wrap it round your box in both directions. Halve these measurements to give the basic bag dimensions. Find the nearest mailing bag size that will take this size plus a bit for packing.Are slim hard backed books suitable for mailing bag?
Hardback books will suffer from depression on the corners whilst being otherwise fine. Slim books are suitable for padded mailing bags.Can I send large bolts and nuts through the post in mailing bags?
Yes, use padded mailing bags (jiffy bags). Pack the items tightly together.Can I send china mugs in mailing bags?
No, use cardboard boxes.Are mailing bags recycled?
The lining of padded mailing bags is made entirely of recycled paper fibres. The outer of the bag is made of pure kraft paper from sustainable forests. The padded mailing bag is totally recyclable as it is all paper.
Mailing bags packaging guide last updated: Jul-2025
