Not all paper sizes are the same, and some things require a certain paper size. These sizes are set by the American National Standards Institute, or ANSI. They’re the same people who standardize bank checks, power tools and numerous figures across the aircraft and space engineering industry, the civil engineering industry and even the clothing industry. Yes, clothing sizes are standardized too, as difficult as it might be to find a well-fitting pair of jeans.

When you’re looking at letter vs. legal paper, there are some obvious differences and a few different situations where you’d want to opt for one over the other. There are some things you should know about two of the most common paper sizes in America.

Tip

Letter-size paper is 8.5" x 11", and legal-size paper is 8.5" x 14".

When Paper Became Standardized

Whether you’re looking at letter vs. legal paper or letter size vs. A4 paper, it’s pretty obvious that there’s a standard. This standard evolved to accommodate monospaced fonts, which take up less space per line. The standard of the ISO A series (which includes A0, A1, A2, A4 and beyond) was set in 1975 and was based on paper used in Germany since 1922.

In America, the letter-size standard, which is similar to A4, was set by the United States government during the 1980s even though it’s been used since the 1920s.

What Size Is Letter-Size Paper?

The dimensions of letter-size paper are 8.5 x 11 inches, or 216 x 279 mm. This is also sometimes called A-size paper, but it’s not the same thing as A4 paper, which is commonly used in the United Kingdom. Odds are that your default printer settings are suited toward letter-size paper unless you’ve marked otherwise in a program like Microsoft Word.

The dimensions of legal-size paper are 8.5 x 14 inches, or 216 x 356 mm. This type of paper is sometimes called "foolscap" after an old, popular brand of paper used a “foolscap,” or joker’s hat, as a watermark logo.

Letter-size paper is used for almost all writing purposes in the U.S. If you’re handing in a college essay or work report, you probably want to use letter-size paper. This smaller size fits in binders, but it’s not always the most convenient.

Legal paper is more commonly used anywhere that a contract would be written because the length of the paper is more conducive to contracts. This includes use within legal professions, accounting and real estate. It’s also ideal for printing spreadsheets, and anyone who has ever tried to print an Excel spreadsheet on letter-size paper knows the pain this can cause.

In the battle of letter vs. legal size, legal paper has some more space, but it’s wholly more inconvenient. It doesn’t always fit neatly in folders and filing cabinets, and drawers often need to be adjusted to fit its extra length. Legal paper doesn’t always work with printers, photocopiers and fax machines. You often have to manually set the machine to print a legal document.

Letter Size vs. A4

The one thing about letter-size paper is that it’s commonly confused with A4. When you’re looking at letter size vs. A4, you’ll definitely find a distinct difference. A4 is the standard paper size in the U.K., but it’s slightly taller than letter size and more narrow in width. The dimensions of A4 are 8.27 x 11.69 inches, or 210 x 297 mm.