International Envelope Paper Sizes

International Envelope Size in cm, inches

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.

Size	Millimeters	Inches
DL size	220 x 110 mm	8.7 x 4.3 in
B4 size	353 x 250 mm	13.9 x 9.8 in
B5 size	250 x 176 mm	9.8 x 6.9 in
B6 size	176 x 125 mm	6.9 x 4.9 in
C3 size	458 x 324 mm	18 x 12.8 in
C4 size	324 x 229 mm	12.8 x 9 in
C5 size	229 x 162 mm	9 x 6.4 in
C6/C5 size	229 x 114 mm	9 x 4.5 in
C6 size	162 x 114 mm	6.4 x 4.5 in
C7/C6 size	162 x 81 mm	6.4 x 3.2 in
C7 size	114 x 81 mm	4.5 x 3.2 in
E4 size	400 x 280 mm	15.7 x 11 in

DL
220 x 110 mm

B4
353 x 250 mm

B5
250 x 176 mm

B6
176 x 125 mm

C3
458 x 324 mm

C4
324 x 229 mm

C5
229 x 162 mm

C6/C5
229 x 114 mm

C6
162 x 114 mm

C7/C6
162 x 81 mm

C7
114 x 81 mm

E4
400 x 280 mm