Paper Sizes

Common questions

What is the difference between A4 and Letter?

A4 is 210 × 297 mm and Letter is 215.9 × 279.4 mm, so A4 is 5.9 mm narrower and 17.6 mm taller. Neither fits inside the other, which is why a document laid out for one reflows when it is printed on the other: usually a lost line at the foot of a page, or a blank page at the end. A4 is the standard almost everywhere in the world, and Letter is the default in the United States, Canada and Mexico. Change the page size in the document rather than scaling at the printer, and the reflow happens once, where you can see it.

What size is legal paper?

Legal is 8.5 × 14 inches, which is 215.9 × 355.6 mm, or 2550 × 4200 pixels at 300 dpi. It is exactly the same width as Letter and three inches longer, so a Letter sheet fits inside a Legal one with 76.2 mm to spare down the page. It is a North American size with no ISO equivalent: the closest ISO sheet by area is C4 at 229 × 324 mm, which is wider and shorter, so a Legal sheet does not go into a C4 envelope flat.

What is A6 paper used for?

A6 is 105 × 148 mm, a quarter of an A4 sheet, and it is the standard postcard and index card size. Small flyers, pocket notebooks and compendium inserts are cut to it as well. It is close to a 4 × 6 inch photo print but not the same: the photo is 3.4 mm narrower and 4.4 mm taller, so an A6 card will not sit square in a 4 × 6 frame.

How many pixels is A4 at 300 dpi?

2480 × 3508 pixels. A4 is 210 × 297 mm, which is 8.2677 × 11.6929 inches, and multiplying by 300 dots per inch gives 2480.3 × 3507.9, rounded to whole pixels. At 150 dpi it is 1240 × 1754 and at 72 dpi it is 595 × 842. Letter comes out in round numbers at every DPI because it is defined in inches: 2550 × 3300 at 300 dpi.

What is the ratio of A series paper, and why do the small sizes not match it?

One to the square root of two, about 1:1.4142. That ratio is what makes halving work: fold any A sheet across its long side and the result is the next size down in exactly the same shape, with nothing to trim. ISO 216 rounds each halving down to the whole millimetre, which nudges the smaller sizes off the exact ratio. A4 at 210 × 297 mm is 1:1.4143, A5 at 148 × 210 mm is 1:1.4189, and A8 at 52 × 74 mm is 1:1.4231. The tool prints the real ratio for each size and says which ones the rounding has moved.

Why does my printed page have margins that are not part of the paper size?

Because those margins belong to the printer, not to the paper. Almost every printer grips the sheet along one or more edges and cannot lay ink there, so it keeps an unprintable band of a few millimetres around the page, and your software then adds document margins of its own on top. A paper size is the sheet itself. The printable area is always smaller, and how much smaller depends on the printer model, which is why no paper size table can tell you.

What size is a business card?

It depends where you are. North America cuts to 3.5 × 2 inches, which is 88.9 × 50.8 mm. Most of Europe uses 85 × 55 mm and Japan uses 91 × 55 mm for the meishi. A bank card, ISO 7810 ID-1, is 85.6 × 53.98 mm, close enough to the European card that a wallet slot made for one takes the other. All four are in the Size list, so you can draw any two against each other.

Which envelope takes an A4 sheet?

C4 takes an A4 sheet flat, at 229 × 324 mm, with 19 mm spare across and 27 mm down. C5 at 162 × 229 mm takes A4 folded once, and DL at 110 × 220 mm takes A4 folded in thirds, which is the standard business letter fold outside North America. The North American equivalent is the No. 10 envelope, 4.125 × 9.5 inches, which takes a Letter sheet folded in thirds.