The A B C’s of Paper Sizes

Why is A4 smaller than A3 paper? Why is there a still a Foolscap refill pad size for school? Why does the printing company squash my flyer or not print it at all when it looked fine on the computer screen? When I need to send a greeting card, what is the right size envelope to pick? These and many other questions about paper sizes will be answered in this informative article.

The A size was introduced by the Germans in 1922 and you can read up about Paper Sizes in the Wikipedia to find out it’s history. In a nutshell it was found by using a very simple mathematical equation you can have a rectangle that when you divide the long edge in half or multiply the short edge by two this will always give your the same proportional size but halving or doubling the total area of paper. Because it’s always more economical for a printer to print multiple copies of a page on a larger sheet of paper than to print it on a smaller sheet more times, the number scale used for it is keeps halving the page size as the number increases. A0 is roughly one square meter of paper, while A1 is half that or ½m 2 , A2 is 1 2 2 or ¼m 2 so on to A4 (which everyone uses) is 1 2 2 2 2 or 1 over 2 4 or 1m / 16m 2  of paper. This sizing keep getting smaller till we reach A8 which is 52mm × 74mm (smaller than a business card) in size or 1/256 of a square meter of paper. With improvements in printing and paper manufacturing technology the A sizes go larger too, 2A0 and 4A0. 4A0 is 4m 2 of paper or a sheet roughly 1.7 × 2.4 metres in size. Another reason why this standard was quickly adopted around the world was because the thickness and cost of paper is measured by weight, it made it very easy to work out costs no matter what size the finished sheet size is. So that’s why we use Grams per Square Metre when we talk about paper weight/thickness because we know that a 80gsm sheet of A4 paper weighs 5 grams because 80 16 = 5.

You may never come across the B ranges of paper sizes unless you work in the printing industry. They are basically an oversized version of the A sizes to allow for such things a bleed and ganging up of complex documents. For instance a B4 is 250 × 353mm in size making giving at least 20mm around each edge for bleed or binding needs. The next common size you will encounter is the C sizes which have been created for the purpose of sizing envelopes. Their measurements sit between the ones used for A & B sizes. In practical terms all you need to remember is the C size will hold the A size flat. For example a C5 envelope holds an A5 sheet of paper flat or a A4 folded in half.

From there we start going into the more interesting paper sizes, which are combination of legacies from traditions centuries old, concessions to technical practically of their times, and countries needs to be unique. I’m only going to briefly touch on the few most common ones you will encounter.

• DL & DLE – DL stands for “DIN lang” (DIN long) common flyer size of 1/3 of an A4 or 210mm x 99mm. It’s also a convenient way of folding a letter and the DLE is the envelope designed to contain it.
• Foolscap – Still found today in some exercise books and refill pads here in NZ. At 210mm x 330mm it’s an archaic size I’ll be glad to see back of. Once upon a time it was used a lot in the legal and other specialised professions, but as computers and personal printers came in with their standardising on A4, these professions have dropped the old size out of simplicity.
• US Letter & US Legal – 8.5 × 11″ (216 × 279mm) and 8.5 × 14″ (216 × 356mm) respectively. Microsoft Office will default to US Letter size should you forget to set your region to New Zealand (It also sets your spelling to US ax color instead of NZ axe colour. ) For the sake of your printer’s sanity and to make sure your get the best out of your printing, avoid these paper sizes if you can.
• Tabloid and Broadsheet –  11 × 17” (279mm × 432mm) and 18 × 24” (457mm × 610mm.) Used exclusively for newspapers, those are sizes that you probably never have to use yourself.
• SRA# – When talking to printing companies like us at Copy Express, you may hear us talk about SRA sizes. SRA is simply a A sizes with at least 15mm added to the length and width. Why that much? Because that gives us the absolute minimum waste paper to print full bleed artwork and have grip edges for the printer to hold on to. Again this is a case where unless you are in the industry you will never have to worry about it.
• Business cards sizes – This is an article in itself as every country has its’ own standards based on tradition and technological limitations. Here in NZ, we use 90mm × 55mm as it’s a slightly shorter version of the Japanese size of 91mm × 55mm so it makes it easy to get the equipment make and store the cards. You may also encounter the US standard of 2 × 3.5” (51mm x 91mm) which turns up a lot because people use the templates found in Microsoft Office. A size that is common is the Credit Card size of 54mm × 86mm because a lots of wallets have pockets only for credit cards.
• Photo sizes – Another one that is worth a article in it’s own right. However there’s a pretty simple rule of thumb for the sizes being that the size is always a ratio of 3:2 in steps of inches with same step up and down scale as A sizes. The standard print size is 6 × 4” which is roughly a A6 (148mm × 105mm). 8 × 6” roughly equals a A5 (210mm × 148mm), a 8 × 12” roughly equals a A4 (297mm × 210mm) and so on.

As I said early on in this article the range of paper sizes is huge and I can only briefly touch on a few of them. Rest assured that if you have to deal with an odd paper size then why not talk to us here at Copy Express and we can sort it out for you with a minimum of fuss and cost.