Paper Size Guide - Never be confused by paper sizes again

September 15, 2015

So how big is A4 exactly I hear you ask? How many A5’s in an A3 and what exactly is a DL paper size? You can find the answer to all these questions and more right here. If you are just after a quick size reference however just scroll down to our paper size table to refresh your memory.

Paper sizes - The basics

On the surface of it paper sizes can be a little bewildering all these seemingly unrelated letters and numbers that mean nothing to the uniformed eye. Once you know what they mean however and how they relate to one another you will be relieved to know it all becomes rather simple. I will start with the most common paper size group, the A series. Standardised by ISO 216 this is group of paper sizes you will most likely already be familiar with. For most people knowledge of this group alone is sufficient. The naming convention for this series is simple, it uses the letter A followed by a number. I am sure you are already familiar with A4. It is likely the size of paper you printer uses, the size of letters you get in the post and pretty much the most commonly used size of paper on the planet.

How the paper sizes relate to one another

Ok that’s great so you know roughly how big an A4 is so what about the rest? Well if you are going up by 1 size from A4 to A3 (The lower the number the larger the sheet) you double the size of the shortest edge. So for instance an A4 sheet measures 210mm x 297mm making its shortest edge 210mm long. An A3 sheet measures 420mm x 297mm. so to move up a size 210 x 2 = 420. This gives an A3 sheet the flat size equivalent of exactly 2 A4 sheets.

Now say for instance we wanted to move up a size to A2. You will notice that the edge that was the shortest previously has now become the long edge. Our current A3 sheet measures 297mm x 420mm. This means that we have to double the side of our new shortest edge, the 297mm edge. So this time we add 297 + 297 = 594. This gives us an A2 size of 420mm x 594mm. You will notice that this is exactly the same size as 2 A3 sheets or 4 A4 sheets.

Starting to make sense? This system works the other way too. Say for instance we wanted to get to an A5 sheet all we would have to do is half the length of the longest edge, in this case 297mm. So 297/2 = 148, this gives us an A5 size of 148mm x 210mm, exactly half the size of and A4 sheet. See not so complicated after all is it. Rather than working it out every time however you can always use our reference table at the top.

So what about business cards & compliment slips?

Because not everything fits the mould...

Compliment Slips

Compliment slips are usually printed on what is known as DL size. This is essentially 1/3 of an A4 sheet if you divide a portrait sheet horizontally. This makes a DL 210mm x 99mm.

Business Cards

There is no set standard size and these do vary in convention from country to country and also due to personal choice. In the UK however we do generally opt for a size of 85mm x 55mm.

Just in case we have left you feeling confused...

Yes the pattern continues past A0 it just takes a different naming convention. After A0 a number precedes the size to indicate how many A0 sheets would fit in it. For instance the size above is 2A0 (Meaning the equivalent of 2 A0 sheets) whilst the size above that is 4A0.

Check out our frequently asked questions for more help on your print related questions.


For quick & easy reference:

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