Large Letter Sized Mailers & Envelopes

Our Large Letter range covers cardboard envelopes and postal mailers — often called PiP (Pricing in Proportion) packaging — designed to fit through a standard letterbox while staying within Royal Mail's Large Letter dimensions (max 353 x 250 x 25mm, up to 750g). This makes them the most cost-effective option for ecommerce sellers shipping small, slim products like jewellery, cosmetics, prints, accessories, and subscription items. Our Large Letter range includes board-backed envelopes, all-board mailers, and peel-and-seal designs in a variety of sizes and finishes — including white, brown, and printed options. For thinner sends, browse our Letter mailers; for thicker items, see our Small Parcel packaging or read our Royal Mail postal sizes guide.