A5 size in inches: 5.83 x 8.27 in. A5 size in centimeters: 14.81 x 21.01 cm. A5 size in millimeters: 148 x 210 mm.
Detailed Measurements for International Paper Sizes & Envelopes.
There are three ranges of sizes, prefixed A, B, and C. The most widely used for general printing and letterhead stationery is the Aseries. The international letterhead size is an A4.
The dimensions of the A series paper sizes, as defined by the ISO 216 standard, are given in the table below the diagram in both millimeters and inches (cm measurements can be obtained by dividing mm value by 10).
Standard International Paper Sizes
Size  Width x Height (mm)  Width x Height (in) 

4A0  1682 x 2378 mm  66.2 x 93.6 in 
2A0  1189 x 1682 mm  46.8 x 66.2 in 
A0  841 x 1189 mm  33.1 x 46.8 in 
A1  594 x 841 mm  23.4 x 33.1 in 
A2  420 x 594 mm  16.5 x 23.4 in 
A3  297 x 420 mm  11.7 x 16.5 in 
A4  210 x 297 mm  8.3 x 11.7 in 
A5  148 x 210 mm  5.8 x 8.3 in 
A6  105 x 148 mm  4.1 x 5.8 in 
A7  74 x 105 mm  2.9 x 4.1 in 
A8  52 x 74 mm  2.0 x 2.9 in 
A9  37 x 52 mm  1.5 x 2.0 in 
A10  26 x 37 mm  1.0 x 1.5 in 
International sizes for envelops
Sizes  Millimeter  Inches  Suitable paper formats 

C4  324 x 229  12 ¾ x 9  A3 folded once or flat A4 
C5  162 x 229  6 3/8 x 9  A3 folded twice, A4 folded once and flat A5 
C6  114 x 162  4 ½ x 6 3/8  A4 folded twice, A5 folded once and flat A6 
C7/6  89 x 165  3 ½ x 6 ½  1/3 A4 
DL  110 x 220  4 ¼ x 8 5/8  A4 folded twice or A5 folded once. 
4A0 & 2A0  The DIN 476 Oversize Formats
The paper sizes bigger than A0, 4A0 & 2A0, aren’t formally defined by ISO 216 but are commonly used for oversized paper. The origin of these formats is in the German DIN 476 standard, which was the original base document from which ISO 216 was derived. 2A0 is sometimes described as A00, however this naming convention is not used for 4A0.
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 meter.
 Each subsequent size A(n) is defined as A(n1) cut in half parallel to its shorter sides.
 The standard length and width of each size is rounded to the nearest millimeter.
Note: For reference the last item is there because the root 2 aspect ratio doesn’t always give a whole number.
International Usage
The A series paper sizes are now in common use throughout the world apart from in the US, Canada and parts of Mexico. The A4 size has become the standard business letter size in English speaking countries such as Australia, New Zealand and the UK, that formerly used British Imperial sizes. In Europe the A paper sizes were adopted as the formal standard in the mid20th century and from there they spread across the globe.
A4 vs A5 and Other Sizes
For Americans, it’s A4 paper that is closest to the most commonly used paper size in the U.S., lettersized, at roughly 8.3 inches by 11.7 inches. A5, on the other hand, is seldom used by the average office worker, as it’s typically used only for creating booklets, leaflets, flyers and other promotional materials. A5 is approximately 5.8 by 8.3 inches in size, and it’s the closest in size to the U.S. paper size called the “halfletter” size, at 5.5 by 8.5 inches.
ANSI Paper Sizes
America is complicated when it comes to papers, because there are the commonly used sizes you may know — halfletter, letter, legal, junior legal and tabloid/ledger — but then there are ANSI sizes, which use the lettersized paper (8.5 by 11) as its base format. They come in sizes A through E.

A is 216 x 279 millimeters, or 8.5 x 11 inches, with an aspect ratio of 1:1.2941. Its closest IS0 216 paper size is A4.

B is 279 x 432 millimeters, or 11 x 17 inches, with an aspect ratio of 1:1.5455. Its closest IS0 216 paper size is A3.

C is 432 x 559 millimeters, or 17 x 22 inches, with an aspect ratio of 1:1.2941. Its closest IS0 216 paper size is A2.

D is 559 x 864 millimeters, or 22 x 34 inches, with an aspect ratio of 1:1.5455. Its closest IS0 216 paper size is A1.

E is 864 x 1118 millimeters, or 34 x 44 inches, with an aspect ratio of 1:1.2941. Its closest IS0 216 paper size is A0.
Applications of formats
ISO has established very definitive measures for paper sizes but not all of these are in common practice except for [A4](https://A4 PAPER) being the most popular. Below is the table to tell the common usage of these formats.
A8, B8  Playing cards 

A3, B4  Newspapers. Used in the photocopying machine other than A4 
C6, C5, C4  Envelops for the A4 letter. No fold C4, one fold C5 and two folds C6 
A6, B6, A5, B5  Books 
A6  Postcards 
A5  Notepads 
A4  Used in photocopying machines, laser printing, catalogs, forms, magazines, letters 
A3, A2  Large tables, diagrams, drawings 
A2, A1  Flip charts 
A1, A0  Posters, technical drawings 
The common purpose that A4 serves is in photocopying. Sometimes it happens that you want to change the format of the papers you want to photocopy. Therefore the machines come with the enhancements of changing the magnification factor to the desired adjustments and also to shift the formats. For example you want to save the paper by printing the journal on an A4 format to two journals on A3 format. For this you should either do the settings of magnification factor into 71% or if the machine has the function of converting A4 to A3 then simply give the input
Commonly Used American Paper Sizes
While these are technically standardized, these do not have shared aspect ratios. Only the ledger/tabloid paper corresponds with anything else, and that’s because lettersized paper is exactly half the size of tabloid paper. It’s the lack of a common aspect ratio that makes life tough for graphic designers, marketers and others who use paper dimensions daily in their work.

HalfLetter: Measures 140 by 216 millimeters, or 5.5 inches by 8.5 inches, with an aspect ratio of 1:1.5455, and this size does not correspond to any ANSI size, but is closest to the ISO 216 size of A5.

Letter: Measures 216 by 279 millimeters, or 8.5 inches by 11 inches, with an aspect ratio of 1:1.2941, the same as size A in ANSI.

Legal: Measures 216 by 356 millimeters, or 8.5 inches by 14 inches, with an aspect ratio of 1:16471, and this corresponds to no other size in either ISO 216 or ANSI papers.

Junior Legal: Measures 127 by 203 millimeters, or 5 inches by 8 inches, with an aspect ratio of 1:1.6000, and this, too, does not correspond to any other paper size with ISO 216 or ANSI.

Ledger/Tabloid: Measures 279 by 432 millimeters, or 11 inches by 17 inches, with an aspect ratio of 1:1.5455, the same as ANSI size B and similar to ISO 216’s size A3.
Why Should You Use ISO 216?
If you’re a business student just whipping up a report for a class, it doesn’t really matter what you use, provided you use the right paper size for how you’ve laid out your document. Letter to letter, A4 to A4. That said, there’s no shortage of international students who’ve come to the USA and panicked about why they can’t get their document to print the full text — and it’s because their document is set up to print on A4, which is 0.2 inches narrower but 0.7 inches longer — just enough to monkey with the margins and leave some text unprinted.
But if you do business internationally and are creating documents to be used in satellite offices around the world, be mindful of the fact that ISO 216 has been the standard for most nations for more than half a century, and they won’t even think about American paper sizes when they’re trying to problemsolve their document printing woes.
The consistent aspect ratio of ISO 216 is the reason you should always, always use Aseries sizes when you’re doing any kind of design work for marketing purposes. Say you create a fantastic poster for an event, and now you decide you want a small card for handing out to passersby on the street. If you’ve made a tabloid/ledgersized poster, your only option for the same aspect ratio is the lettersized paper. But if you’d designed with an ISO 216 size in mind, like A1, then sizing down to something like an A6sized flyer will be easily achieved.
It’s all about the Aspect
Whoever devised the ISO 216 sizes for paper did a brilliant job, because the aspect ratio being the same across all the sizes makes your life easier for all kinds of designing and printing applications. Marketing materials become infinitely more adaptable when all you need to do is change size parameters rather than having to resize elements to fit a whole new document’s different aspect ratio.
The attributes of ISO series 3:
Series A
The aspect ratio of the series is √2 (rounded to 1414). Before rounding A0 to the nearest millimeter, its area is 1 square meter. The stack size (A1, A2, A3, etc.) is determined by dividing the area of the previous sheet size by half and rounding up so that the long side A (n + 1) is the same length as the short side.
Therefore, each continuous size is almost half of the abovementioned size, so an A1 page can accommodate 2 A2 pages in the same area. A4 is 210 mm by 297 mm (0.27 inches), which is almost exactly 0.0625 square meters. In contrast, the letterhead size commonly used in North America (8 1⁄2" x 11", 216 mm x 279 mm) is 6 mm (0). It is 24 inches wider and 18 mm shorter than A4. Therefore, the A5 paper size is half of the A4 paper size, such as 148 mm x 210 mm (5.8" x 8.3"). As shown in Figure 2, the A series maintains the aspect ratio of each subsequent rectangle after being cut or folded in half perpendicular to the larger side.
For rectangles with longer x sides and shorter y sides, make sure that the x/y aspect ratio matches the y/x/2 rectangle, which is half the size. H.X / y = y / x / 2 is simplified as x / y =√2; in other words, the aspect ratio is 1:√2. Approximate size (cm).
B Series
The definition of line B in the standard is as follows:
"The size of another line is obtained by continuous geometric positioning between adjacent dimensions of line A. Using geometric average, each step: B0, A0, B1, A1, B2. Every time it is less, and the previous step is multiplied by the same multiple. Like series A, the aspect ratio of series B is √2 plus half (rounded to the nearest millimeter) to get the next line.
The smallest surface B0 is specifically 1 meter. There is also an inappropriate Japanese B series. According to JIS, its calibration space is 1.5 times that of the corresponding JISA series. (Such as ISOA series). Accordingly, the range of JISB series paper is 1.5 moments the length 1.22 times matching: ISO B series paper is 4√2≈1.19 terms greater than Aseries paper.
C Series:
The setting of the C series is {price} based on the form of B series, and includes the format of A3 series, and its range is constant (for example, C2 is the geometric mean between B2 and A2). As for the A and B series, the ratio is √2, and the C series size is mainly used for envelopes. C4 envelopes can be used for A4 pages. The aspect ratio of C series envelopes is the same as that of A3 series envelopes. For example, if you fold an A4 page in half, it will fit in a C5 envelope (this is the size of a C4 envelope folded in half).
Therefore, the length of ISO C series paper is 8√2≈1.09 times its length. Size series paper. Dimensions A3, B, and C are matched as part of the geometric gradient, and the continuous aspect ratio is 8√2, although there is no dimension between Bn and A (n 1): A4, C4, B4, D4", A3size. There is such a D series in the Swedish extended version of the system.
What is Legal Paper Size?
Europe and other places in the World use the international system of paper sizes. In that system, the legal paper size is A4 document, which has dimensions of 216 x 279mm (8.5 inches x 11 inches). However, in America and Canada, there is a different legal paper size, which is 216 x 356mm or 8.5 inches x 14 inches.
In the international paper size system, sizes are based on mathematical formulas. However, in America, that is not the case. So, when creating a legal document, you need to pay attention to the size and dimensions of your document. Especially if your document should be printed and signed. No matter if the document is signed electronically or in hardcopy, the size should match the legal parameters. Otherwise, the document will not be legally binding and obligating.
A Series Paper Sizes Formal Definition
The ISO 216 definition of the A paper sizes is based on the following basis:

The length divided by the width is 1.4142

The A0 size has an area of 1 square meter.

Each subsequent size A(n) is defined as A(n1) cut in half parallel to its shorter sides.

The standard length and width of each size is rounded to the nearest millimeter.
Note: The last item is there because the root 2 aspect ratio doesn’t always give a whole number.
Cut Writing Paper Sizes
The following table gives the sizes in inches and mm of the British imperial cut writing paper sizes.
Size  Width x Height (in)  Width x Height (mm)  Aspect Ratio 

Albert  4.0 x 6.0 in  101.6 x 152.4 mm  1:1.5 
Duchess  4.5 x 6.0 in  114.3 x 152.4 mm  1:1.3333 
Duke  5.5 x 7.0 in  139.7 x 177.8 mm  1:1.2727 
Foolscap Quarto  6.5 x 8.0 in  152.4 x 203.2 mm  1:1.2308 
Foolscap Folio  8.0 x 13.0 in  203.2 x 330.2 mm  1:1.625 
Small Post Octavo  4.5 x 7.0 in  114.3 x 177.8 mm  1:1.5556 
Small Post Quarto  7.0 x 9.0 in  177.8 x 228.6 mm  1:1.2857 
Large Post Octavo  5.0 x 8.0 in  127.0 x 203.2 mm  1:1.6 
Large Post Quarto  8.0 x 10.0 in  203.2 x 254.0 mm  1:1.25 
Frequently Asked Questions
1 Is A5 the same as 8.5 x11?
A5 Size. Letter size paper is 8.5 x 11 inches (215.9 x 279.4 mm), whereas A5 size paper is 5.8 x 8.3 inches (138 x 210 mm).
2 What is A5 paper size used for?
A5 has many uses. This size is a popular choice for diaries & planners, books, invitations, flyers, booklets and more. A6 paper is typically used for postcards, flyers, leaflets and save the dates. A7 tends to be used for large Postit notes.
3 Is A5 half of A4?
For example, the dimensions of A4 paper are 210x297mm, and half of A4 equals A5, and double A4 equals A3. Starting from A0, all subsequent A paper sizes are determined by halving the paper on its longest size.
4 Is A5 paper legal size?
Half letter: 5.5 inches wide by 8.5 inches in height (140 x 216 mm). Closest to A5. Legal: 8.5 inches wide by 14 inches in height (216 by 356 mm)
5 Is B5 bigger than A5?
The B paper sizes are a bit larger than their A series counterparts and are based on the geometric mean of two consecutive A series sheets. For example, B4 is between A3 and A4 in size, and B5 is between A4 and A5.
6 How many A4 is A5?
While several mobile printers offer A5 printing facilities, many standard home printers offer A5 prints, as it is half the size of A4, allowing two A5 prints to be printed on one sheet of A4.
7 What is A5 compared to A4?
The A4 is a fiveseat, fourdoor saloon, the A5 a twodoor coupe and the A5 Sportback a fourdoor coupe. The A5 Sportback has more space for rear passengers, so is still sleeker than the A4 but has a longer roofline.
8 What’s half the size of A5?
An A5 piece of paper measures 148 × 210 mm or 5.8 × 8.3 inches. Cutting it in half will create two A6 sheets of paper. An A5 piece of paper will fit into a C5 envelope. When folded in half, it will fit into a C6 envelope.
9 Is A5 a 7x5?
A5 format was standardized at the same time that all A sizes, in 1975 by ISO 216 standard. The A5 has the following dimensions: 210 x 148 mm or 8.27 x 5.83 inches. Its printable surface is reduced when applying the usual print margins: 160 x 108 mm.
10 What aspect ratio is A5?
Two A5 pages next to each other in a spread equals the A4 paper size. This way a range of paper sizes are created from A0 (which has a surface of one square meter) to A10. The height/width ratio remains constant (1:1.41 or the square root of 2) for all sizes.
CONCLUSION:
A5 size in inches: 5.83 x 8.27 in. A5 size in centimeters: 14.81 x 21.01 cm. A5 size in millimeters: 148 x 210 mm.
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