Best Envelopes & Mailing Supplies

Common questions

What size envelope do I need to avoid extra postage?

In the UK, Royal Mail charges by size and thickness, so a Large Letter costs more than a standard Letter. Keep items under the Letter limits where you can, around 24 by 16.5cm and 5mm thick. C5 and DL envelopes usually qualify as Letters, while C4 counts as a Large Letter. Check current Royal Mail guidance before buying.

Are padded or bubble mailers worth the extra cost?

For anything fragile or valuable, yes. Padded and bubble-lined mailers cushion against knocks in transit and cut the chance of damage claims, which costs far more than the mailer. For flat, sturdy items, plain mailing bags are cheaper and lighter. Match the protection to the contents, and buy in bulk to keep the unit cost low.

What is the difference between mailing bags and envelopes?

Mailing bags are plastic or padded and suited to clothing, soft goods and non-fragile items, with a strong self-seal for postage. Paper envelopes suit documents and card, and rigid ones protect photos or certificates. For posting products, waterproof mailing bags from brands like Triplast keep contents dry. Choose by contents, weight and how much protection they need.