Side-by-Side Comparison
C-Series Envelopes (ISO 269)
C4 Envelope vs. C6 Envelope
Comparing 2 standards across 8 specifications. 8 key differences identified.
Comparing:
C4 Envelope
C6 Envelope
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.
The C6 envelope is an ISO 269 standard compact postal envelope measuring 114 × 162 mm (4.49 × 6.38 inches). Designed to enclose an A4 sheet folded in half twice (cross-folded in quarters) or an unfolded A6 picture postcard (105 × 148 mm), it is the global standard for personal correspondence, holiday cards, and gift certificates.
Specification Comparison Table
8 Parameters| Parameter / Spec | ||
|---|---|---|
|
Width × Height (Metric)
|
229 × 324 mm | 114 × 162 mm |
|
Width × Height (Imperial)
|
9.02 × 12.76 in | 4.49 × 6.38 in |
|
Geometric Mean Origin
|
Geometric mean of A4 (210×297 mm) and B4 (250×353 mm) | Geometric mean of A6 (105×148 mm) and B6 (125×176 mm) |
|
Target Paper Pairing
|
Unfolded A4 paper (210 × 297 mm) or flat-folded A3 sheet | A4 folded into quarters (105 × 148 mm) or flat unfolded A6 cards/postcards |
|
Paper Insertion Clearance
|
+19 mm width / +27 mm height allowance | +9 mm width / +14 mm height clearance |
|
Primary Applications
|
Legal contracts, commercial catalogs, official certificates, passport mailings | Personal handwritten letters, greeting cards, holiday cards, RSVP response cards |
|
Common Variants
|
Pocket (short-edge flap opening) or Banker/Wallet (long-edge opening) / Board-backed 'Do Not Bend' | — |
|
Weight of Empty Envelope
|
— | ~4.0 to 5.5 grams |