Envelopes & Window Envelopes

Choose the Right Envelope Size

The envelope format depends on the size of the document and whether it needs to be folded. C4 is suitable for A4 documents sent unfolded, while C5 is designed for A4 sheets folded once. C6 is used for A4 sheets folded twice, and E65 is suitable for A4 documents folded into three sections.

For a more detailed overview of dimensions and formats, see our guide to envelope sizes and envelope types.

Window Envelopes and Sealing Options

Window envelopes are practical for invoices, customer letters, and other recurring mailings where the recipient's address is already printed on the document. Make sure the window position matches the address field on your printouts. Envelopes without windows are a good choice if you prefer to write the address directly on the envelope or use address labels.

Also consider how the envelopes will be sealed. Gummed envelopes are sealed by moistening the adhesive, while self-sealing envelopes do not require moisture. For peel-and-seal envelopes, the protective strip is removed before sealing. Choose the sealing method that best suits your workflow and mailing volume.

Envelopes with Extra Protection

Need to send documents or small items that require additional protection during transport? Explore our range of bubble mailers and padded envelopes.