Side-by-Side Comparison
C-Series Envelopes (ISO 269)
C3 Envelope vs. C4 Envelope
Comparing 2 standards across 9 specifications. 9 key differences identified.
Comparing:
C3 Envelope
C4 Envelope
The C3 envelope is an ISO 269 standardized large postal packet format measuring 324 × 458 mm (12.76 × 18.03 inches). Designed specifically to hold flat, unfolded A3 documents (297 × 420 mm) or thick bound A4 portfolios, it is the standard packaging for architectural presentations, financial ledgers, and artwork shipments.
The C4 envelope is an ISO 269 standard postal packet measuring 229 × 324 mm (9.02 × 12.76 inches). Sized specifically to enclose a full unfolded sheet of A4 paper (210 × 297 mm) with comfortable margin, it is the worldwide standard for mailing legal contracts, university diplomas, annual corporate reports, and magazines.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Width × Height (Metric)
|
324 × 458 mm | 229 × 324 mm |
|
Width × Height (Imperial)
|
12.76 × 18.03 in | 9.02 × 12.76 in |
|
Geometric Mean Origin
|
Geometric mean of A3 (297×420 mm) and B3 (353×500 mm) | Geometric mean of A4 (210×297 mm) and B4 (250×353 mm) |
|
Target Paper Pairing
|
Unfolded A3 (297 × 420 mm) or bound A4 spiral/comb portfolios | Unfolded A4 paper (210 × 297 mm) or flat-folded A3 sheet |
|
Primary Applications
|
Architectural drawings, financial balance sheets, graphic design proofs, diploma certificates | Legal contracts, commercial catalogs, official certificates, passport mailings |
|
Standard Paper Clearance
|
+27 mm width / +38 mm length allowance for easy insertion | — |
|
Common Closure Types
|
Peel-and-seal strip, string-and-button, cardboard gusset pocket | — |
|
Paper Insertion Clearance
|
— | +19 mm width / +27 mm height allowance |
|
Common Variants
|
— | Pocket (short-edge flap opening) or Banker/Wallet (long-edge opening) / Board-backed 'Do Not Bend' |