Standard Paper Sizes – Understanding Standard Paper Sizes

Have you ever noticed the different numbers on a box of printer paper? Do you know what these numbers signify?  Additionally, do you understand the difference between Tabloid, A5, and A4 papers? In this article, we will be guiding you through all of the different paper sizes and guidelines, and helping you understand the uses of the different paper sizes.  



An Overview of Standard Paper Sizes

Before any paper existed, people used to communicate by drawing symbols and pictures that were carved into tree bark, or hand-painted on cave walls. Marks were also made on clay tablets or papyrus. Then, around 2000 years ago, the Chinese crafted cloth sheets that were used to record writings and drawings, which led to the creation of paper.  

Paper was originally produced in China in the fifth century by Ts’ai Lun, who was a court official. He used mulberry bark, rags, and hemp and mixed them with water.

He then mashed it into a pulp and pressed out all the liquid, making it into a thin mat, and hung it out in the sun to dry. Ts’ai’s discovery soon traveled to the Middle East, as we know it today, but it was only 500 years later that the making of paper started in Europe. The very first paper mill was established in Spain, and soon after mills appeared across Europe.

General Standard Paper Sizes

England began making paper in the late 15th century and was soon supplying paper to all its colonies. Then in 1690, the United States built its first paper mill in Pennsylvania using the old Chinese method of shredding cloths and rags into fibers. However, as the demand for the use of paper increased in the country, they started to use fibers from trees, as it was cheaper than cloth. Today, special forests are grown and managed, and paper is still made from trees or recycled.

There are only two main standard paper-size systems in use globally. These include the ISO (International Organization for Standardization), and the ANSI (American National Standards Institute).

The ISO international standard, referred to as ISO 216, is used in most countries of the world. The North American system, referred to as ASME Y 14, is governed by the ANSI (American National Standards Institute) and is used in the USA, Canada, the Philippines, Chile, and parts of Mexico. The ISO paper standard is metric, so all the measurements are in millimeters, whereas the ANSI paper standard is imperial, so all the measurements are in inches. The ISO paper standard has only one aspect ratio of 1:2, whereas the ANSI has two aspect ratios of 4:3 and 3:2. 


Definition of the ISO Standard Paper Sizes 

The ISO 216 Standard Paper Size is an international paper standard used for designating the size of a sheet of paper. This ISO-size method involves height-to-width proportions, where the height and width of the pages correlate with one another, like the diagonals of a square. To put it in simple terms, when a sheet of any ISO system paper size is folded in half, along the longest side, then it forms the next smaller size of paper in the system. 

ISO paper sizing is centered on the metric system, where the width, as well as the height of all pages, are measured off to metric lengths. 

Metric Paper Sizes Chart

Paper is usually identified by height-to-width proportions in grams per square meter, making it easier to calculate the mass of any document when the format of all the pages is known. The ISO paper size system is divided into three main groups: the A-series, B-series, and the C-series.


The A-Series Paper Sizes   

The A-series paper sizes are used for general paper sizes that are used in books, ledgers, posters, and more. In the A-series paper sizes, the A0 paper has an area of one square meter, and the A1 paper size is half of the height of the A0 paper size. This principle is also used for all the other smaller sizes of paper. The width as well as the height of the paper is rounded-off in millimeters.  


The B and C-Series Paper Sizes   

The B-series paper sizes were introduced to give a more extensive variety of paper sizes. To explain this a little better, a size B-series paper size falls between the A-series paper size. This means that the B1 paper size falls halfway between the A0 and the A1 paper sizes.

The C-series paper sizes were specially designed for envelopes, and they were made to fit all of the A and B-series paper.

This means that a piece of A4 paper size that is unfolded will fit perfectly into a C4 envelope. Also, a piece of A4 paper folded, forming an A5 paper size, fits perfectly into a B5 envelope. To explain the ISO paper size system more clearly, refer to the paper size chart below. All the dimensions are in millimeters. 

Paper Sizes Chart

A-Series Paper SizesB-Series Paper SizesC-Series Paper Sizes
A0841 x 1189B01000 x 1414C0917 x 1297
A1594 x 841B1707 x 1000C1648 x 917
A2420 x 594B2500 x 707C2458 x 648
A3297 x 420B3353 x 500C3324 x 458
A4210 x 297B4250 x 353C4229 x 324
A5148 x 210B5176 x 250C5162 x 229
A6105 x 148B6125 x 176C6114 x 162
A774 x 105B788 x 125C781 x 114
A852 x 74B862 x 88C857 x 81
A937 x 52B944 x 62C940 x 57
A1026 x 37B1031 x 44C1038 x 40


Popular ISO Paper Sizes 

What is a normal paper size? The standard ISO paper size system covers an extensive range of paper formats. However, not all of them are used daily, the A4 paper size is the normal and most common, which is widely used daily for office use. In the paper size chart below we will give you more of the most used paper formats and their application. 

Standard Paper Sizes In Inches

Paper SizeApplication
A0 and A1Posters and Technical drawings
A1 and A2Flip charts
A2 and A3Diagrams, large tables, and drawings
A4Magazines, books, forms, letters, catalogs, copying, and laser printing
B5, A5, B6 and A6Books
C4, C5 and C6Envelopes
B4 and A3Copying machines and newspapers
B8 and A8Playing cards


A4 Paper

A4 Is the most common of all the paper sizes and is used extensively in most parts of the world for printing and stationery. The size, according to the ISO 216 standard, is 210 x 297 mm. So, what makes this paper size more important than all the other paper sizes? A larger piece of paper gives you more space to write and draw on, but it also takes up a lot more space. So, the size of the paper you choose will be determined by the purpose.

Most of the school books and notepads used by students are an A4 size because they need to carry them around in their backpacks all day long.

What Is A Normal Paper Size

This means that they need to be the right size to fit into their backpacks, but have enough space to write and draw on. Most magazines and letters are also printed on A4 paper size, making it much easier to store and transport. Most copying and computer printers are equipped for the A4 paper size, and you can also modify the format when changing it from portrait to landscape format.


A3 Paper

The A3 paper size is twice as large as the A4 and measures 297 x 420 mm. This makes it a very versatile size, perfect for signs, posters, leaflets, and menus. It is also used extensively by professionals as well as for personal use for printing and mounting photos and other designs.


A5 Paper

The A5 paper size is half the A4 size, measuring 148 x 210 mm. This is an ideal size for notebooks, greeting cards, diaries, flyers, leaflets, and brochures. It is also the perfect size for graphic design and can easily fit into your handbag or purse when you are traveling.

Common Paper Size


B4 Paper

The B4 paper size was developed to provide a wider range of paper sizes. The B4 paper size measures 250 x 353 mm and is larger than an A4 paper size and lies between the A3 and A4 paper sizes. The B4 paper size is suitable for writing but is not suitable for printing on a computer printer as they are not compatible. They are more suited for editing tables, little posters, and notes.

The B-series paper sizes were specially designed to fit neatly into the C-series envelopes.


B5 Paper

Similar to the B4 paper size, the B5 cannot be printed on a computer printer as they are not compatible. This paper size is more suited for printing magazines and advertising leaflets and creating menus. It is also used for making notebooks and pads and was also developed to fit neatly into the C-series envelopes.

US Letter Size


Advantages and Disadvantages of Using the ISO Standard Paper Sizes 

The size of the paper can affect the everyday working experience, like office work, and drafting in a drawing office, schools, and colleges. So, we need to understand the advantages when working with the ISO 216 standard paper sizes.   There must be a standard size for paper for everyone to follow and use, which is why paper sizes were standardized.

The size of a sheet of paper affects many things, such as binders for filing, envelopes, filing cabinets, printer trays, picture frames, documents, and more.

Letter Paper Size


  • Drawings that are produced on very large sheets of paper can be reduced to more convenient sizes. The ISO standard paper sizes make this possible.
  • It is a lot more economical and eco-friendly to print standard-size sheets.
  • ISO envelope sizes are designed to fit standard-size paper sheets, so you can buy any envelope in the store, and it will take your paper sheet size.


  • Folding of the ISO paper sizes is an issue.
  • The ISO paper sizes are mostly used for office business documents and home use on the computer.



Definition of the North American Standard Paper Sizes 

Paper sizes in the USA were not designed to fall in with the mathematical formula like the ISO sizes. This is because the paper was manufactured by hand and the molds used were 44 inches x 17 inches creating eight 8.5 x 11-inch pieces that were known as the U.S. letter size.  In 1922, the ANSI (American National Standards Institute) officially classified the sizes of letter paper and legal paper. In 1995, this officially became the ANSI/ASME Y14.1 standard for paper sizes.

The various formats of the paper sizes in this standard are represented by ANSI, and then a letter follows indicating the paper size.

The North American or ANSI standard does not use the same paper size as the ISO standard, instead, they use Letter, Legal, and Ledger/Tabloid paper sizes that are contained in the ASME Y14.1 standard. Below are some examples of standard paper sizes in inches.

What Are Standard Paper Sizes

Size of paperWidth x height (Inches)Aspect ratio
Half letter5.5 x 8.51:1.5455
Government letter8.0 x 10.01:1.25
Letter8.5 x 11.01:1.2941
Junior legal5.0 x 8.01:1.6000
Government legal8.5 x 13.01:1.5294
Legal8.5 x 14.01:1.6471
Ledger/Tabloid11.0 x 17.01:1.5455

The U.S. letter size (8.5 x 11 inches) is known as the A-size, which is followed by the B, C, D, and E-sizes, where the A-size paper is the letter size and the B-size is the ledger or tabloid size. As the ISO standard uses one single ratio for each size, the ANSI standard uses two ratios, which makes reducing and enlarging the paper sizes more complicated. See below for ratios and comparisons.

Different Paper Sizes Chart

Size of paperWidth x Height (Inches)Aspect ratioClosets ISO size
A8.5 x 11.01:1.2941A4
B11.0 x 17.01:1.5455A3
C17.0 x 22.01:1.2941A2
D22.0 x 34.01:1.5455A1
E34.0 x 44.01:1.2941A0

There is also a B-plus or Super B-size that measures 13 x 19 inches, which is designed with a one-inch margin all around that makes provision for printing bleed. This is also accepted as a Super A3 size. With the ANSI standard, there is also an architectural size designed for architectural purposes. This has a ratio of 4:3 and 3:2, such as the ratio used on computer screens. To explain the ANSI paper size system more clearly, refer to the table below.