# item.guide
Side-by-Side Comparison C-Series Envelopes (ISO 269)

C3 Envelope vs. DL Envelope

Comparing 2 standards across 11 specifications. 11 key differences identified.

Comparing:
C3 Envelope
DL 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.

View full C3 Envelope spec sheet →

The DL envelope (Dimension Lengthwise / DIN Lang, standardized under ISO 269 and DIN 678) measures 110 × 220 mm (4.33 × 8.66 inches). Engineered specifically to hold an A4 sheet folded horizontally in thirds (Z-fold or C-fold), it is the dominant standard across Europe and most of the world for automated corporate billing, bank statements, and commercial direct-mail advertising.

View full DL Envelope spec sheet →

Specification Comparison Table

11 Parameters
Parameter / Spec
Width × Height (Metric)
324 × 458 mm 110 × 220 mm
Width × Height (Imperial)
12.76 × 18.03 in 4.33 × 8.66 in
Target Paper Pairing
Unfolded A3 (297 × 420 mm) or bound A4 spiral/comb portfolios Standard A4 sheet folded in thirds horizontally (99 × 210 mm)
Geometric Mean Origin
Geometric mean of A3 (297×420 mm) and B3 (353×500 mm)
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
Primary Applications
Architectural drawings, financial balance sheets, graphic design proofs, diploma certificates
Paper Insertion Clearance
+11 mm height / +10 mm width clearance
Address Window Position
Standard DIN window: 45 × 90 mm, located 20 mm from left, 15 mm from bottom
Automated Insertion Standard
High-speed optical inserter machine standard (thousands of pieces/hour)
Comparison to US #10
DL is 110 × 220 mm; US #10 is 4.125 × 9.5 in (104.8 × 241.3 mm)