Bad enough that half of the globe is using meters and metric, and half (or less) is using inches and feet, but then we had to go and institute enough different size-standards for paper to make your head spin! There are common names for some of them; there's ANSI format, and Arch format, and some of them have letters and some of them have numbers, and then there are modifiers, like 'super'. What does it all mean?

If you just got a gig doing illustrations for a magazine overseas, and they want the art in a specific size in letters and numbers that mean nothing to you, this should help you figure out what you're being asked for.

About the Standards

The International Organization for Standardization, ISO, is the global standardization department of Darn Near Everything. Because, globally, metric is the acceptable unit system, the ISO sheet sizes are set at round milimeter numbers, which makes for pretty funky inch measurements.

American National Standards Institute, or ANSI, is the most common English-unit system. These sizes are the standard letter sizes that Americans are most used to.

JIS is the Japanese International System. Like the ISO system, this one was created for the metric system.

DIN is Deutsches Institut für Normung e.V. (the German Institute for Standardization). Another system designed for metric units.

Architectural, or Arch (usually not in all upper caps like the other standards, since it's an abbreviation, not an acronym). The Architectural system is similar to the ANSI system and made for English units, but runs to base 6 numbers: 12, 18, 24 and 36.

Architectural

Architectural sheets are classified by letter. You'll usually, but not always, see the prefix 'Arch' with the letter, IE: Arch D. These are the sheet sizes commonly used by architectural and engineering firms. A D-sized sheet is the most common for architectural plan sets. You may also hear a C sheet referred to as a half-sized D or half-D, as half-scale D-sized plots are printed to this size.

*The military often requires engineering and architectural plans on this size sheet.

ANSI

Probably, if you live in America or the UK, the common paper size is 'letter-sized', or ANSI A. ANSI sizes also go by letter.

ISO

ISO standards are papers sized for the metric system, so they fall into fractional inch-sizes and whole metric-sizes. They are based off of a ratio of 1 to square root of two, if you care for that much detail. The terms used for ISO papers all start with A or B and then count by number. The A sizes are 'American,' the B sizes are 'European'.

JIS

The Japanese International System sizes are all preceeded with a B and count down in size by number.

DIN The German Institute for Standardization sizes are all preceeded with a C and count down in size by number.

Oddball Paper Size:

Most of the sizes make a little bit of sense if you look at them all together. The letters or numbers go up or down with size, the page ratio stays the same and each step between sizes uses the dimension of the long side of the previous side as the dimension of the short side of the new size.

But, of course, they had to go and make things difficult and throw in just a few very popular sizes that don't fit any of the standards. US Legal is probably the most common of these. This page is 8.5 x 14 inches (215.9 x 355.6 mm). This is an important size to note mostly because most printers and copiers can handle this size, and it's used in most US legal documentation. Executive paper is also common, at 7.5 x 10 inches (190 x 254 mm), as is ledger or tabloid paper (another term for the 11 x 17, ANSI B paper)

Another oddball size, the 13 x 19 paper has earned its own bracket in the ISO and ANSI standards, showing up as ANSI Super B and ISO Super A3.

Photo Sizes:

Standard photo and art sizes are not to be confused with paper sizes! Photo standards are based on the ratio of a 35 mm negative, and then there are a range of common sizes which are close to that and used extensively in the photo and art reproduction industry. Most standard cut mats and frames are based on photo standards. It is best to plan your piece for one of the standard photo sizes, print it on the next closest standard paper size, and then assume it will be matted up to the next standard photo/frame size. This will save your customers from having to pay for custom matting and framing and allow them to purchase something off the shelf.

*The most common sizes; mats and frames of these sizes would be available at just about any framing or art supply store. Other sizes listed aren't uncommon, but they aren't as universal.

Mind your letters!

Now you know the Ps and Qs... or rather, the As and Bs of paper size.