C Envelope Paper Sizes

C Envelope Size in cm, inches

C series paper sizes and dimensions are defined by the ISO 269 international paper size standard. The C series is usually used for envelopes. The area of C series paper is the geometric mean of the areas of the A and B series paper of the same number. For example, the area of a C4 sheet is the geometric mean of the areas of an A4 sheet and a B4 sheet. This means that C4 is bigger than A4, and somewhat smaller than B4. The practical usage of this is that a letter written on A4 paper fits inside a C4 envelope, and both A4 and C4 paper fits inside a B4 envelope.

C Envelope Paper Sizes
Size Millimeters Inches
C0 size 917 x 1297 mm 36.1 x 51 in
C1 size 648 x 917 mm 25.5 x 36.1 in
C2 size 458 x 648 mm 18 x 25.5 in
C3 size 324 x 458 mm 12.8 x 18 in
C4 size 229 x 324 mm 9 x 12.8 in
C5 size 162 x 229 mm 6.4 x 9 in
C6 size 114 x 162 mm 4.5 x 6.4 in
C7 size 81 x 114 mm 3.2 x 4.5 in
C8 size 57 x 81 mm 2.2 x 3.2 in
C9 size 40 x 57 mm 1.6 x 2.2 in
C10 size 28 x 40 mm 1.1 x 1.6 in
C0
917 x 1297 mm
C1
648 x 917 mm
C2
458 x 648 mm
C3
324 x 458 mm
C4
229 x 324 mm
C5
162 x 229 mm
C6
114 x 162 mm
C7
81 x 114 mm
C8
57 x 81 mm
C9
40 x 57 mm
C10
28 x 40 mm