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International Envelope Paper Sizes

Further Information

The standard envelope sizes are defined by the international standard ISO 269. They are generally designed to be used with paper sizes that follow the ISO 216 standard. The most commonly used envelope sizes are from the C series. An A4 piece of paper will fit into a C4 envelope. The DL envelope has a different aspect ratio to the C series, which is why it does not appear in that series. The DL envelope is the most common envelope used in business. DL is short for ‘Dimension Lengthwise’, however it was previously known as DIN Lang in Germany where it originated in the 1920s. An A4 sheet of paper folded three times, parallel to its smaller sides, will fit into a DL envelope.

Format Width × Height (mm) Width × Height (in)
DL 110 × 220 mm 4.3 × 8.7 in
B4 250 × 353 mm 9.8 × 13.9 in
B5 176 × 250 mm 6.9 × 9.8 in
B6 125 × 176 mm 4.9 × 6.9 in
C3 324 × 458 mm 12.8 × 18 in
C4 229 × 324 mm 9 × 12.8 in
C4M 318 × 229 mm 12.5 × 9 in
C5 162 × 229 mm 6.4 × 9 in
C6/C5 114 × 229 mm 4.5 × 9 in
C6 114 × 162 mm 4.5 × 6.4 in
C64M 318 × 114 mm 12.5 × 4.5 in
C7/C6 81 × 162 mm 3.2 × 6.4 in
C7 81 × 114 mm 3.2 × 4.5 in
CE4 229 × 310 mm 9 × 12.2 in
CE64 114 × 310 mm 4.5 × 12.2 in
E4 220 × 312 mm 8.7 × 12.3 in
EC45 220 × 229 mm 8.7 × 9 in
EC5 155 × 229 mm 6.1 × 9 in
E5 115 × 220 mm 4.5 × 8.7 in
E56 155 × 155 mm 6.1 × 6.1 in
E6 110 × 155 mm 4.3 × 6.1 in
E65 110 × 220 mm 4.3 × 8.7 in
R7 120 × 135 mm 4.7 × 5.3 in
S4 250 × 330 mm 9.8 × 13 in
S5 185 × 255 mm 7.3 × 10 in
S65 110 × 225 mm 4.3 × 8.9 in
X5 105 × 216 mm 4.1 × 8.5 in
EX5 155 × 216 mm 6.1 × 8.5 in