Royal Mail and Courier Guidelines for Sending Padded Envelopes
Royal Mail and courier rules for padded envelopes: sizes, weights, and postage rates.
Royal Mail guidelines
Quick answer
Small padded envelopes (up to size C/D) can qualify for Royal Mail large letter rates if total thickness stays under 25mm and weight under 750g. Larger sizes ship as small parcels. Always measure the packed, sealed envelope as padding and contents add significant thickness. Courier pricing is based on weight and dimensions, with most charging by whichever is greater: actual or dimensional weight.
Large letter qualification
Small enough and thin enough when packed with slim items.
Padding plus contents often pushes total thickness to 25mm or beyond.
Empty envelope thickness is misleading. Contents add significantly.
Small sizes with thin items genuinely qualify for large letter rates.
Size guide: size and lining or e-commerce savings.
Courier guidelines
Most UK couriers (DPD, Evri, DHL, UPS) classify padded envelopes by weight and dimensions using dimensional weight formulas. Padded envelopes are generally lighter and cheaper to ship than boxes of equivalent internal capacity.
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Postage-optimised padded envelopes
Padded envelopes sized for Royal Mail rates from ProcuraPack.
Browse padded envelopesFrequently asked questions
Small sizes (A, B) can if packed thickness is under 25mm and weight under 750g.
353mm x 250mm x 25mm thick, up to 750g.
Always packed. Contents and padding add significant thickness.
Usually yes, due to lower weight and smaller dimensions.
Most classify by weight and dimensions the same as any other package.
Part of our guide
Product Guide: Padded Envelopes
Expert guides on padded envelopes and cushioned mailers for safe, cost-effective shipping.
Browse all guides →
