Filters
C4 Envelopes - Everything You Need to Know
Why choose C4 envelopes?
C4 envelopes are the go-to choice whenever you need to post or present A4 documents without folding. At competitive wholesale prices, our C4 range suits offices, solicitors, accountants and businesses that demand a neat, professional finish for letters, brochures, certificates and contracts.
Key benefits
- No folding: A4 paper (210 × 297 mm) slips in flat - ideal for formal documents.
- Variety: plain white, gusset, coloured, window and board-back options available.
- Security & protection: padded and gusseted types provide extra protection for thicker items.
- Branding: full-colour printing, logo placement and spot inks for corporate presentation.
- Sustainability: recycled and FSC-certified papers available for low environmental impact.
Practical information & specifications
- Standard dimensions
- 229 × 324 mm (approx. 9.02 × 12.76 in)
- Fits
- A4 documents flat (no folding required)
- Common materials
- 80-120 gsm paper, kraft (brown), recycled fibres, board for board-back types, bubble-lined for padded versions
- Closures
- Gummed (traditional), self-seal (peel & seal), and clasp/metal fasteners (special types)
- Window options
- Single window (address), landscape or portrait orientation; clear plastic or paper windows available
- Minimum order (custom)
- Depends on print process - typically from 250 to 1,000 units (contact us for precise MOQ)
Buying guide - choose the right C4 envelope
1. Decide what you’re sending
For single A4 sheets or a thin brochure, a standard paper C4 (80-100 gsm) is usually fine. For thicker booklets, certificates or multi-page reports, consider a board-back or padded C4 for extra rigidity and protection.
2. Choose the closure
Peel & seal (self-seal) is fast and ideal for busy offices. Gummed closures have a more traditional finish but require moistening. For long-term storage, board-back with clasp or reinforced strip is best.
3. Window or no window?
Use windowed C4 envelopes if you want the recipient address on the content to be visible through the envelope. For formal documents or branded presentation, plain panels give a cleaner look.
Custom printing & branding
Custom printed C4 envelopes help promote your brand at the point of delivery. We offer single-colour and full-colour printing and return address printing. Typical print processes include digital (for smaller runs) and litho/offset (for larger runs).
- Full-colour front or back printing
- Spot UV or varnish for a premium finish (subject to minimums)
- Personalisation and variable data printing for mailshots
Need a quote? Contact our print team with artwork in PDF at 300 dpi and CMYK colours. We'll confirm proofs and lead times. Email us now for a quotation
Postage & mailing considerations
Postage classification (Large Letter, Small Parcel, etc.) depends on weight and thickness - check Royal Mail or your chosen carrier for exact limits. A single A4 sheet in a paper C4 is often heavier than a standard letter; when in doubt weigh a sample before buying postage in bulk.
- Measure the finished thickness and weight to determine postage class.
- Padded C4 will normally be classed as a parcel and cost more to send.
- For international posting, ensure customs forms are completed correctly and consider using tracked services for important documents.
Hints & Tips for Using C4 Envelopes
- Avoid overstuffing: Prevent tearing and postage issues by not overfilling. Use padded or board-back C4 envelopes for thicker documents.
- Professional presentation: Plain or coloured envelopes without windows look neat for proposals, contracts, and certificates. Custom printing or logos can boost your branding.
- Mailing efficiency: Pre-sort by size and weight to save time and postage costs. Self-seal C4 envelopes are ideal for high-volume mailings.
- Document protection: Use padded or board-back envelopes to prevent bending and damage during transit, especially for fragile or multi-page documents.
- Recycling tips: Choose recycled or FSC-certified envelopes when possible. Remove plastic windows before recycling to ensure proper processing.
Frequently asked questions
A standard C4 envelope measures 229 × 324 mm (approximately 9.02 × 12.76 inches), large enough to accept A4 paper flat without folding.
Yes - A4 (210 × 297 mm) fits flat inside a C4 envelope with space to spare, making C4 ideal for documents, certificates and brochures that must remain unfolded.
Common types include plain paper C4, manilla (brown) C4, windowed C4 (single or double), padded/bubble-lined C4 for protection, board-back C4 for rigidity and customised printed C4 for branding.
Many C4 envelopes are recyclable, especially those made from plain paper or recycled fibres. Plastic windows can hinder recycling in some local schemes - remove windows if required by your local council. We also offer FSC-certified and recycled options.
Self-seal (peel & seal) is faster and preferred for high-volume mailings. Gummed (lickable) is traditional and can look neater for archiving. For frequent mailings, self-seal is usually most efficient.