Paper sizes affect many things. Envelope sizes, binders, printer trays, file cabinets, mail service, frames, documents – just to name a few. Many objects need to be designed with the correct paper dimensions in mind. The standardization of paper sizes simplifies this process.

Standard paper sizes differ depending where you live. While most of the world uses the ISO 216 standard for paper sheet sizes, the North American system is slightly different and features dimensions that are easier to express in inches.

At a glance, here are the ISO A-Series international paper sizes and the North American paper size standards.

A-Series International Standard Paper Sizes

Used around the world.

Size Other Names Width x Height (in) Width x Height (mm)
A0 (-) 33.1” x 46.8” 841mm x 1189mm
A1 (-) 23.4” x 33.1” 594mm x 841mm
A2 (-) 16.5” × 23.4” 420mm x 594mm
A3 Ledger, Tabloid 11.7” × 16.5” 297mm x 420mm
A4 Letter 8.3” x 11.7” 210mm x 297mm
A5 (-) 5.8” × 8.3” 148mm x 210mm
A6 (-) 4.1” × 5.8” 105mm x 148mm
A7 (-) 2.9” × 4.1” 74mm x 105mm
A8 (-) 2.0” × 2.9” 52mm x 74mm

 

Standard Paper Sizes in North America

Used primarily the in the United States, Canada, and the Philippines.

Size Other Names Width x Height (in) Width x Height (mm)
Letter ANSI A 8.5” x 11” 216mm x 279mm
Legal (-) 8.5” x 14” 216mm x 356mm
Tabloid ANSI B 11” × 17” 279mm x 432mm
Ledger ANSI B 17” x 11” 432mm x 279mm
Junior Legal (-) 5” × 8” 127mm x 203mm
Half Letter Memo, Statement 5.5” × 8.5” 140mm x 216mm
Government Letter (-) 8” × 10.5” 203mm x 267mm
Government Legal (-) 8.5” × 13” 216mm x 330mm
ANSI C (-) 17” × 22” 432mm x 559mm
ANSI D (-) 22” × 34” 559mm x 864mm
ANSI E (-) 34” × 44” 864mm x 1118mm
Arch A (-) 9” × 12” 229mm x 305mm
Arch B (-) 12” × 18” 305mm x 457mm
Arch C (-) 18” × 24” 457mm x 610mm
Arch D (-) 24” × 36” 610mm x 914m
Arch E (-) 36” × 48” 914mm x 1219mm
Arch E1 (-) 30” × 42” 762mm x 1067mm

 

Who determines paper size standards?

In the United States, standard paper sizes are decided by the American National Standards Institute, or ANSI. The norm in which all standardized paper dimensions can be found is called ANSI Y14.1.

In the rest of the world, the International Organization for Standardization, or ISO, presides over the regulation of paper sizing. ISO 216 is the internationally recognized norm for paper sizes.

Other paper standards do exist. And different countries have their own institutes responsible for developing norms. But the ANSI and ISO systems are the most common paper size standards around the world.

 

What are the differences between ISO standards and North American standards?

There are several key differences between the paper sizes laid out in ISO 216 and those used in North America.

Most importantly, North American standards are designed for the imperial measurement system rather than the metric system. Letter size paper in the USA measures an easy-to-remember 8.5 by 11 inches. To compare, the closest ISO equivalent, A4 paper, measures 210 × 297 mm. That equals 8.27 x 11.7 when expressed in inches, which is a decidedly less user-friendly number.

Another important difference between North American and international paper sizes is the aspect ratio. ISO A-Series paper always has an aspect ratio of 1 to √2. This means that the height and width relate to each other in the same way that the side and diagonal of a square do.

iso a-series paper sizes

A lifesize model demonstrating the square-root aspect ratio of ISO’s A-series paper standards in a museum in Barcelona. By S.Wetzel, CC BY-SA 4.0, 

Standard paper sizes in the United States, however, do not have a consistent aspect ratio.

The differences are hardly noticeable to the naked eye. Most people wouldn’t perceive the difference in dimensions between standard US letter size paper and ISO A4 paper unless they were placed side by side.

standard paper sizes chart

A chart showing how North American standards for paper sizes differ from the ISO A-series sizes. Image by Wikipedia user Bromskloss, CC BY-SA 3.0

 

Are there other standard paper series?

While A-size paper is the most commonly used around the world, there are other paper sizes as well. ISO 219 also includes a B-Series and C-Series. The B-Series has slightly wider dimensions, which makes them a great size for posters. The C-Series are also a bit wider than the A-Papers, which is why they are often used for envelopes: A-Series papers can easily slide inside of envelopes with C-Series dimensions.

standard envelope sizes

What are SRA paper sizes?

ISO 219 includes a series of RA and SRA paper sizes. SRA stands for “Supplementary Raw Format A,” and these standard sizes are meant to be used for documents that are to be trimmed.

SRA paper sizes include an additional bleed area and have dimensions that are exactly 105% the size of the corresponding A-Series paper sizes. That means SRA4 has dimensions 5% greater than A4, SRA3 has dimensions 5% greater than A3,  SRA2 has dimensions 5% greater than A2, and SRA1 has dimensions 5% greater than A1, etc. etc.

 

What is foolscap paper?

Foolscap is an outdated paper size that was once commonly used in record keeping in the Imperial UK. It is roughly 0.5″ wider and 2.0″ longer than U.S. letter paper.

 

What are the most common paper sizes often used for?

The standard sizes for paper find many uses. Here are some of the most common applications of various standard paper sizes.

 

U.S. Letter and A4 size paper

U.S. letter size and A4 size paper are by far the most common paper sizes. Your typical home or office printer is programmed to print these sizes by default. These are also the sizes in which you are likely to find the most options in terms of paper formats, colors, and materials.

Letter/A4 paper is often used for flyers, booklets, notepads, letterhead, and any number of other daily printing needs.

Ledger/Tabloid and A3 size paper

Ledger/Tabloid paper, and its closest ISO paper size equivalent A3, is often used in record keeping. Wills, deeds, and other important financial transactions are typically printed on ledger paper, whose slightly heavier weight gives it a higher degree of durability and permanence.

Leger Paper is also used for small posters, flyers, and brochures.

U.S. Legal paper

U.S. legal paper has the same width as U.S. Letter paper (8.5″), but it measures 3.0″ longer (14.0″). It is most commonly used for letters and other formal documents.

 

What is the standard business card size?

Like standard paper sizes, business card dimensions vary around the world. Read more about the different standards for business card sizing and printing on our blog.

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