Plain Self-Seal Envelopes - Convenient and Secure Mailing Solutions

Plain Self-Seal Envelopes are the ideal solution for sending documents, letters, or small parcels securely and conveniently. These high-quality envelopes feature a self-adhesive sealing strip that eliminates the need for glue, tape, or moisture, ensuring fast, easy, and secure closure. Available in a variety of sizes, our plain self-seal envelopes are perfect for both business and personal use, making them a versatile choice for all your mailing needs.

Plain Self-Seal Envelopes – Everyday Letter & Large Letter Mail | Pack Exact

Plain Self-Seal Envelopes

Everyday plain self-seal envelopes for business post, statements, invoices, invites and general mail. Fast peel-and-seal closures, clean presentation and sizes from C6 and DL through C5 and C4.

Looking for rigid, bend-proof options? See All Board Envelopes (stay-flat) or expandable Cardboard Pocket Envelopes for 0–50 mm capacity.

Packing books, LPs or thicker items? Choose ColomPac Book Wraps or ColomPac Fast Assembly Boxes.

What are self-seal envelopes?

Paper envelopes with an adhesive strip protected by a release liner. Fold the flap, press to seal—no tape or moisture required. Ideal for high-throughput mailrooms and eCommerce despatch.

Why choose ours

Fast fulfilment: peel-and-seal closure speeds packing and reduces mess.

Professional look: crisp, plain finish for branded letters or printed inserts.

Recyclable: paper-based construction simplifies end-of-life.

Ideal uses

Business mail: statements, invoices, order confirmations, returns paperwork.

Marketing: flyers, invites, vouchers—pair with address & brand labels.

Admin & archive: paperwork, contracts, certificates (use stay-flat for bend-sensitive items).

eCommerce inserts: pack slips, returns forms with Documents Enclosed wallets.

International mail: clean, secure seal with tidy presentation.

Sample kits (flat): thin swatches or cards—use all board if rigidity is needed.

Selecting the right size

Envelope sizeFitsTypical mail classUse casesTips
C6A6 card (A5 folded)LetterInvites, thank-you cards, vouchers Use heavier paper for premium feel
DL1/3 A4 (A4 folded in thirds)LetterInvoices, statements, mailers Great balance of cost and presentation
C5A5 (A4 folded once)Letter / Large LetterBooklets, forms, catalogues (thin) Watch thickness to stay in Letter band
C4A4 (no fold)Large LetterCertificates, reports, proposals Use all board to prevent bending

For rolled posters or plans, switch to Postal Tubes.

How to pack efficiently

1) Pick the footprint: C6/DL/C5/C4 to match inserts—avoid over-tight fits.

2) Organise inserts: keep corners aligned; add a thin cardboard sheet for premium packs.

3) Seal cleanly: peel liner, fold and press once; no extra tape needed.

4) Label & docs: apply labels and, for parcels, add Documents Enclosed.

Complete your postal pack

Postal & flat mailers

Postal Envelopes · All Board Envelopes · Cardboard Pocket Envelopes · Book Wraps

Boxes

ColomPac Fast Assembly · Single Wall · Double Wall

Accessories

Labels · Documents Enclosed Wallets · Protective Paper · Bubble Wrap · Packing Tape

Plain Self-Seal Envelopes – Frequently Asked Questions

Self-seal uses an adhesive strip with a release liner—just peel and press. Gummed needs moisture to activate the glue and is slower for volume mailing.

Use C4 for A4 without folding or C5 for A4 folded once. For bend-sensitive items, pick All Board.

Yes—these are paper-based and widely recyclable. Remove any non-paper inserts before recycling.

Choose a slightly larger footprint, keep inserts aligned, and add a thin cardboard pad. For maximum rigidity, use All Board Envelopes.

For thicker mail (0–50 mm), use Cardboard Pocket Envelopes. For books, LPs or mixed items, choose Book Wraps or Fast Assembly Boxes.

Yes—custom print is possible on many lines. Pair with labels for rapid branding.


Why Choose Our Plain Self-Seal Envelopes?

  • Self-Adhesive Seal: The self-adhesive strip allows for quick and easy sealing without the need for glue or tape. Simply peel and seal for a secure closure.
  • Efficient and Time-Saving: The self-sealing design speeds up the packing process, saving you time and reducing the effort required to prepare items for mailing.
  • High-Quality Construction: Made from durable, lightweight paper, these envelopes are strong enough to protect your documents or items during transit while remaining cost-effective.
  • Available in Various Sizes: Our plain self-seal envelopes come in a variety of sizes to accommodate different types of documents, letters, and small parcels, ensuring that your items fit perfectly.
  • Cost-Effective: Plain self-seal envelopes are an affordable and reliable solution for businesses and individuals who need to mail documents or small items regularly.
  • Professional Appearance: These envelopes offer a clean, simple look that enhances the presentation of your mail, ensuring that your correspondence appears neat and professional.
  • Easy to Use: Simply remove the peel-off strip and press to seal the envelope securely, making them hassle-free to use in busy office environments or at home.

Shop Plain Self-Seal Envelopes in Various Sizes

  • DL Plain Self-Seal Envelopes: Ideal for standard-sized documents such as invoices, letters, and certificates. A popular size for everyday mailing needs.
  • C4 Plain Self-Seal Envelopes: Perfect for mailing larger documents, brochures, and magazine-sized items. Offers ample space for a variety of items.
  • C5 Plain Self-Seal Envelopes: Suitable for smaller documents, photos, and smaller letters, these envelopes offer an excellent balance of size and protection.
  • C6 Plain Self-Seal Envelopes: Designed for compact items such as small cards or invitations. Ideal for businesses that need to send smaller correspondence.
  • Custom Plain Self-Seal Envelopes: We offer custom-sized plain self-seal envelopes for businesses with specific packaging needs. Contact us for more details on custom orders.

Single Wall Boxes - FAQs and More

Why Plain Self-Seal Envelopes Are the Right Choice

Plain self-seal envelopes provide a simple yet secure way to send documents, letters, and small parcels. Their self-adhesive sealing strip allows for quick and easy closure, ensuring that your items are securely sealed for transit. Available in a range of sizes, these envelopes are perfect for everyday mailing needs and are an essential item for businesses and individuals. The high-quality construction of these envelopes ensures durability and protection, while the clean, simple design offers a professional look for your mailings.

Frequently Asked Questions About Plain Self-Seal Envelopes

Plain self-seal envelopes are made from high-quality paper, providing a durable and lightweight solution for mailing documents and small items. They feature a self-adhesive strip for easy sealing without the need for glue or tape.

We offer plain self-seal envelopes in a variety of sizes, including DL, C4, C5, and C6. Custom sizes are also available for businesses with specific packaging needs. Contact us for more details on custom orders.

While plain self-seal envelopes are excellent for mailing documents, photos, and small items, they may not provide sufficient protection for fragile or highly valuable items. For fragile items, consider adding additional protective packaging like bubble wrap or foam inserts.

Yes, our plain self-seal envelopes are made from recyclable materials, making them an eco-friendly packaging solution. After use, they can be recycled, helping to reduce waste and minimize environmental impact.

Yes, plain self-seal envelopes are suitable for both domestic and international shipping. They meet the postal requirements for various destinations worldwide and provide secure protection for your items during transit.

Sealing plain self-seal envelopes is easy. Simply peel off the protective strip on the adhesive, fold the flap over, and press to seal the envelope securely. No glue or tape is required.

Yes, we offer custom plain self-seal envelopes for businesses that need specific sizes or branding. You can add your logo or company details for a professional touch. Contact us for more information on custom orders.