The board is the second question. The first is the shape of the goods. This topic separates the shapes we sell and the note you should keep when one of them works.
The shape before the board is the comparison. Measuring a box you will buy again is the record.
Six shapes, not one catalogue
A stack of product wants a cube from boxes. A fast ecommerce desk, packing the same small goods, may want a crash lock: base locks open, peel-and-seal strip, 150K/T board, six sizes listed as fitting Royal Mail small parcels. A book or a slim kit wants a book wrap or an M-envelope box. A poster wants a postal tube. Files want an archive box, one-piece A4 with handles, sides triple thickness once made up. Hanging clothes want a wardrobe box with a rail, and those sizes are internal.
White postal boxes are a finish on a postal cube, white 125WK/T, described as qualifying as a small parcel, some with foam in a shell-and-slide. They are not wraps and they are not wardrobe boxes. Archive, wardrobe and white boxes keeps that split. Single wall and double wall is the board, after the shape is right. Single wall is the everyday board. Double wall is the stronger UK-made board for heavy, fragile or stacked goods.
PayPal branded packaging is a printed outer for sellers who want that face. It is not a new shape. Treat it as the cube it is, and still measure. Box shapes is this page. The guides under it are the detail of each silhouette.
The outside, if it will be posted
Royal Mail small parcel maximums on our changes page are external: 450 × 350 × 160 mm. A roll can be a small parcel at up to 450 mm long and 80 mm in diameter. A cube measurement does not describe a tube. Tape and a bulge count. The goods do not. Postal tubes and book wraps are the flat and long notes. Crash lock boxes lists the six sizes in full.
Internal and external differ by the thickness of the board. Double wall steals more cavity and adds more outside than single wall. Wardrobe sizes are stated as internal. If you change board, measure again. Measuring a box you will buy again is the discipline: goods measurement, carton measurement, shape, board, unit, all on one line, kept where the reorder is placed.
A note that only says three numbers will be ordered as the wrong shape. Say the shape in words. Say millimetres. Say whether the number is the cavity or the outside. Then pack one finished sample, shake it, and measure the outside if it is posted, before the note becomes the standing order.
Reordering the shape you proved
The product pages are pack quantities of one carton. Buy the quantity you will send and can store. A perfect size in an enormous pack is the wrong buy if you have nowhere to put it. Orders placed by 3pm leave the same day. UK delivery is free over £50 ex VAT. TradePro, for trade businesses, starts at 5% and goes to 10% over £1,000 a month. Use the account on the size you have packed and measured, not on five candidates.
Stocked items can be returned within 14 days if an unproved size was wrong. Call and arrange it before the cartons are taped into the day’s orders. A “slightly bigger one” added in a busy week becomes the new standard without a measurement. Do not let it. If the goods change, write a new note and prove a new sample.
How a box size is chosen is the shorter article. Together with the shape guide, it is the whole decision: silhouette, board, outside limit, written record. Everything else on the box shop is a range you open after that, not instead of it.
One shape on the shelf, not a museum of them
After the sample is proved, the shelf should hold that shape in the quantity you send. A second shape is justified by a second product, not by curiosity. Book wraps next to cubes are correct if you send both books and boxed goods. Book wraps next to cubes “in case” are how the wrong one gets grabbed on a busy afternoon. The shape before the board is the argument. The shelf is the enforcement.
Strength still waits its turn. If the proved cube crushes, move that size to double wall and measure the outside again. Do not add a second, larger single wall carton beside it and hope packers pick the strong-looking one. Single wall and double wall is the board note. The written record should change on the day the board changes, so the next reorder is not the old line.
Orders placed by 3pm leave the same day, so a corrected shape does not need a long pause in dispatch. Use that. A wrong shape left in place for a month because “we have stock” is a month of fill, damage or postage you did not need to buy. Return what you can within 14 days, call first, and let the note be the only size anyone is allowed to reorder.
When someone new starts packing, show them the note and one made-up sample, not the whole of boxes. The catalogue is where you go to change the note. The bench is where the note is followed. A packer who browses sizes mid-shift will invent a second standard by lunchtime. The shape was already chosen. Their job is to repeat it, and to say something if the goods no longer fit the sample. That conversation is cheaper than a week of the wrong cartons, and it only happens if the note is where they pack, not filed with the invoices.
A tube, a wrap and a cube can all be “about the right length” and still be three different packs. If the goods changed from a flat mailer insert to a boxed product, retire the wrap instead of keeping both “for a bit”. Old shapes that linger are how the written record stops being trusted. One live shape per product, named in the words the category uses, is the whole of this topic once the measuring is done.