How to Pack Your Parcel for an InPost Locker

For clothing, textiles, soft toys and anything else that does not need rigid protection, a polythene mailing bag is the right packaging: it is light, waterproof, and it lets the contents settle and compress, so the same jumper takes a Medium compartment in a bag and a Large in a box. A box is for things that must not bend or be crushed: shoes with a box the buyer wants, ceramics, electronics without batteries, books that need their corners protected. Even then, choose the smallest box that protects the item and fill the gaps so nothing moves, because a loose, rattling box measures bigger than it needs to and arrives damaged.

Every InPost compartment is 38 cm wide and 64 cm high. Only the depth changes, at 8 cm (Small), 19 cm (Medium) and 41 cm (Large), and the door closes only if the packed parcel is under that depth at its thickest point. So after packing, stand the parcel on its edge against a ruler or tape and read the thickest point, tape and bulges included. A parcel exactly at the limit will not close; treat anything within a centimetre as the next size up. On Vinted and eBay you choose the compartment on the locker screen, so this measurement is what you are choosing.

For a Small compartment (8 cm deep) a C4-sized or small polythene bag suits a single light garment, a slim book or accessories; fold T-shirts in thirds and roll socks and scarves tightly. For a Medium (19 cm) a 35 × 50 cm bag takes most single items: jeans folded in thirds, a jumper, a dress, shoes without the box. For a Large (41 cm) a 50 × 60 cm or 60 × 80 cm bag takes coats, boots, boxed shoes and bundles. Bags are cheap in packs of 50 online, and a slightly bigger bag that closes flat beats a small one that bulges.

• Small (8 cm): C4 or small polythene bag; T-shirts, slim books, phone cases, jewellery
• Medium (19 cm): 35 × 50 cm bag; jeans, jumpers, dresses, shoes without the box
• Large (41 cm): 50 × 60 cm or 60 × 80 cm bag; coats, boots, boxed shoes, bundles

Seal the bag or box completely with parcel tape; the locker is self-service, so nothing will be re-taped for you, and a flap that springs open stops the door closing. InPost routes the parcel by the QR code or the label the locker prints, so no address is required, but write the recipient's name and address on the outside anyway: if the internal label is damaged in transit the written address lets InPost complete the delivery. Reused boxes are fine if they are sound and every old barcode and label is covered or removed; an old barcode that gets scanned can misroute the parcel.

Do not wrap clothing in bubble wrap: it protects nothing and adds depth. Do not overstuff a bag until it bulges; use the next size up and keep it flat. Do not use a box for a coat, which can double its depth. Do not leave loose filler rattling in an oversized box. And do not set off without checking the InPost app, because the right compartment being free matters as much as the parcel fitting it.

Two jumpers sold as a Vinted bundle. In a shoebox-sized carton they measure 23 cm deep, so a Large, and the street locker near the station has no Large compartments free at 6pm. Folded in thirds, stacked and sealed in a 50 × 60 cm mailing bag with the air pressed out they measure 14 cm: a Medium, of which that locker has five free. The seller writes the buyer's name and address on the bag, scans the QR code, chooses Medium, and the door closes first time.