Single-wall, double-wall and postal boxes ranked by what they protect and which postage size they keep you in, from Large Letter to medium parcel.
You need three box sizes at most: a slim one for Large Letter items, a small parcel box, and a sturdier box for trainers or heavier goods.
Choose board strength by weight, the way you choose size by postage band. Single-wall board suits light items, and double-wall board survives the stacking and drops a heavy parcel meets in a depot.
The criteria that set the order. Commission plays no part.
Fold-up boxes that keep most small items inside the small parcel size.
Typical price
£18to £28
Cheap boxes for light items that need shape more than strength.
Typical price
£8to £14
Stronger board for trainers and anything heavy or easy to break.
Typical price
£22to £34
Slim boxes that protect small items at Large Letter postage.
Typical price
£14to £22
Each step in the order you'll need it.
Single-wall board has one fluted layer between two liners. It is light and cheap, and fine for items under about a kilo that cannot crack.
Double-wall board has two fluted layers. Use it for boxed trainers, electronics, glass and anything heavy, where a dented corner leads to a complaint.
Kit for this step
Royal Mail caps a Large Letter at 25 mm thick, 750 g and 353 by 250 mm across. Its small parcel tops out at 2 kg in a 45 by 35 by 16 cm space, and a medium parcel at 20 kg in 61 by 46 by 46 cm.
Pick boxes that sit a little inside those limits with room for padding. A box 1 cm too deep can push you up a whole price band.
A boxed pair of adult trainers needs roughly 18 × 12 × 8 inches with padding. Books, figures and beauty sets fit small die-cut postal boxes.
Jewellery, coins and graded cards suit Large Letter boxes, so long as the packed box stays under 25 mm thick.
A clean, rigid box from a supermarket or your own deliveries works well. Cover or remove every old label and barcode so the sorting machines read only yours.
Skip boxes with soft corners or water marks. They give way under the weight of other parcels.
The packed box can be no thicker than 25 mm, no heavier than 750 g, and no larger than 353 by 250 mm. Check Royal Mail's current size guide before you buy postage.
For boxed trainers, yes. Buyers expect the shoe box to arrive without dents, and double-wall board resists crushing.
Up to 2 kg, in a box no bigger than 45 by 35 by 16 cm, on Royal Mail.
Yes, if the box is rigid and you cover every old label and barcode.
In our typical bands, 25 small single-wall boxes run £8 to £14, and 15 large double-wall boxes £22 to £34.
Most close with tabs, but a strip of tape over the lid stops it opening in transit.
