C Series Envelope Sizes

C Series Envelope Sizes

The dimensions of the C series envelope sizes, as defined by ISO 216, are given in the table below in both millimetres and inches. The diagrams to the right show the size of each of the envelopes when compared to a sheet of A4 paper.

Table of Envelope Sizes From C0 to C10

Size	Height x Width (mm)	Height x Width (in)
C0	1297 x 917 mm	51.5 x 36.1 in
C1	917 x 648 mm	36.1 x 25.5 in
C2	648 x 458 mm	25.5 x 18.0 in
C3	458 x 324 mm	18.0 x 12.8 in
C4	324 x 229 mm	12.8 x 9.0 in
C5	229 x 162 mm	9.0 x 6.4 in
C6	162 x 114 mm	6.4 x 4.5 in
C7	114 x 81 mm	4.5 x. 3.2 in
C8	81 x 57 mm	3.2 x 2.2 in
C9	57 x 40 mm	2.2 x 1.6 in
C10	40 x 28 mm	1.6 x 1.1 in

C Series Envelope Size Tolerances:

Tolerances specified in ISO 216 for the C series envelope sizes are the same as for A & B series paper sizes and are as follows:

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in)
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in)
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in)

C Series Envelope Size Definitions:

C envelopes sizes are defined as the geometric mean of the A and B sizes with the same number i.e. C4 dimensions are the geometric mean of A4 and B4. This produces a size between the two that makes an envelope that will neatly hold the A series paper of the same size, thus a C4 envelope is perfect for an A4 sheet of paper unfolded.

It should be noted that C format envelopes also have an aspect ratio of 1:root2 and because of this an A4 sheet folded parallel to its shortest sides will fit in a C5 envelope and folded twice will fit a C6 envelope.

DL Envelope Size - The Business Envelope Extension

One of the most widely used business envelopes, the DL format does not fall under the C series sizes as it has a different aspect ratio. This envelope originated in Germany in the 1920's and was known as DIN Lang, but DL is now more commonly expanded to 'Dimension Lengthwise'. This size is defined in the ISO standards for envelope sizes, as the standard would have been remiss in omitting the most commonly used business envelope size.

The dimensions of DL are 110 x 220 mm (4⅓" x 8⅔") and as such the DL envelope will hold an A4 sheet of paper folded into 3 equal sections parallel to its shortest sides.

Despite complaints from manufacturers of automatic enveloping machines that it is slightly too small for reliable enveloping and the introduction of a C6/5 envelope at 114 x 229 mm, the original DL size continues to be most commonly used.

B Series Paper Sizes

B Series Paper Sizes

The dimensions of the B series paper sizes, as defined by ISO 216, are given in the table below in both millimetres and inches. The B Series paper size chart to the right is a visual explanation of how the B paper sizes relate to each other.

Table of Paper Sizes From B0 to B10

Size	Height x Width (mm)	Height x Width (in)
B0	1414 x 1000 mm	55.7 x 39.4 in
B1	1000 x 707 mm	39.4 x 27.8 in
B2	707 x 500 mm	27.8 x 19.7 in
B3	500 x 353 mm	19.7 x 13.9 in
B4	353 x 250 mm	13.9 x 9.8 in
B5	250 x 176 mm	9.8 x 6.9 in
B6	176 x 125 mm	6.9 x 4.9 in
B7	125 x 88 mm	4.9 x. 3.5 in
B8	88 x 62 mm	3.5 x 2.4 in
B9	62 x 44 mm	2.4 x 1.7 in
B10	44 x 31 mm	1.7 x 1.2 in

B Series Paper Size Tolerances:

ISO 216 specifies tolerances for the production of B series paper sizes in the same way as for A series paper sizes, the specific details of which are as follows:

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in)
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in)
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in)

B Series Paper Sizes Definition

The B series paper sizes are defined in ISO 216 in the following way.

The B series paper sizes were created in order to provide paper sizes that weren't covered by the A series, but also use an aspect ratio of 1:root2. B sizes are defined as size B(n) being the geometric mean of size A(n) and size A(n-1). The Geometric Means of 2 numbers being the square root of the product of the two numbers.

This system gives a useful property for enlarging and reducing documents in that the enlargement from A(n) to B(n) is the same as that from B(n) to A(n-1).

As with the A series paper the standard lengths and widths are rounded to the nearest millimetre.

A Series Paper Sizes

A Series Paper Sizes

The dimensions of the A series paper sizes, as defined by ISO 216, are given in the table below in both millimetres and inches. The A Series paper size chart to the right gives a visual explanation of how the sizes relate to each other.

Table of Paper Sizes From 4A0 to A10

Size	Height x Width (mm)	Height x Width (in)
4A0	2378 x 1682 mm	93.6 x 66.2 in
2A0	1682 x 1189 mm	66.2 x 46.8 in
A0	1189 x 841 mm	46.8 x 33.1 in
A1	841 x 594 mm	33.1 x 23.4 in
A2	594 x 420 mm	23.4 x 16.5 in
A3	420 x 297 mm	16.5 x 11.7 in
A4	297 x 210 mm	11.7 x 8.3 in
A5	210 x 148 mm	8.3 x 5.8 in
A6	148 x 105 mm	5.8 x 4.1 in
A7	105 x 74 mm	4.1 x. 2.9 in
A8	74 x 52 mm	2.9 x 2.0 in
A9	52 x 37 mm	2.0 x 1.5 in
A10	37 x 26 mm	1.5 x 1.0 in

To obtain paper sizes in centimetres, convert mm values to cm by dividing by 10.

4A0 & 2A0 - The DIN 476 Oversize Formats:

4A0 & 2A0 aren't formerly defined by ISO 216 but are commonly used for oversized paper. The origin of these formats is in the German DIN 476 standard, that was the original base document from which ISO 216 was derived.

A Series Paper Size Tolerances:

ISO 216 specifies tolerances for the production of A series paper sizes as follows:

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in)
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in)
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in)

A Series Paper Sizes Defined:

The A series paper sizes are defined in ISO 216 by the following requirements:

• The length divided by the width is 1.4142
• The A0 size has an area of 1 square metre.
• Each subsequent size A(n) is defined as A(n-1) cut in half parallel to its shorter sides.
• The standard length and width of each size is rounded to the nearest millimetre.

Note: The last item is there because the root 2 aspect ratio doesn't always give a whole number.