Royal Mail Large Letter vs Small Parcel

Royal Mail’s consumer products still sell on named size bands, not on dimensional weight. For clothes, prints, and small crafts the decision is almost always Large Letter versus Small Parcel. The prices are different products; this page is about the physical test, not today’s 1st Class tariff.

Large Letter: maximum 35.3 × 25 × 2.5 cm and 750 g. It is meant to go through a UK letterbox (the 25 mm slot is the point). Small Parcel: maximum 45 × 35 × 16 cm and 2 kg. Once you need a box, you are usually here.

Sorting offices use gauges and 3-D scanners. A poly mailer that looks A4 but puffs to 28 mm because of a folded hoodie is a Small Parcel, even if it is under 750 g. The surcharge lands on the recipient as underpaid postage, or the item comes back.

Sellers who list on Etsy or Vinted feel this on sub-£15 items: the step from Large Letter to Small Parcel can cost more than the marketplace fee. Measure the packed item, not the garment on the table.

Length is the longest outer side, width the next, thickness the shortest, including tape and bulge. Weigh on a scale, not a guess. Tubes are different: Small Parcel max length 45 cm and length + 2×diameter ≤ 104 cm.

Use the UK parcel size checker with the packed dimensions. It classifies the band in the tab and does not quote a live price. After you know the band, price it on Click & Drop or your own labels.