Paper and Envelope sizes | Learning Hub | Fineline Print & Web

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I’m Alec from Fineline and today I want to help demystify paper and envelope sizes because I know they can confuse quite a bit of confusion.

The great news is that there’s really only a couple of things you really have to know, and the first thing is that A sizes as in A4 is for paper and C sizes as in C4 is for envelopes. But let’s start with paper and we’ll come to envelopes in just a moment.


Paper Sizes

The basis for all paper measurements is an A0 sheet - which just happens to be one square metre. And its dimensions are: 841mm x 1189mm.

Each size down is half the size of the one before – so A1 is half the size of A0 and A2 is half the size of A1 and so on.


A0 841 x 1189 mm

A1 594 x 841 mm

A2 420 x 594 mm

A3 297 x 420 mm

A4 210 x 297 mm

A5 148 x 210 mm

A6 105 x 148 mm

A7 74 x 105 mm

A8 52 x 74 mm

A9 37 x 52 mm

A10 26 x 37 mm


Key Facts:

  • A is for paper sizes
  • All the sizes stem from an A0 sheet which is one square metre.
  • Starting with A0 size - each size down is half the size of the one before.


Before we leave paper sizes I just want to mention another couple of acronyms which you may come across and these relate to RA and SRA sizes. In the interest of jargon busting we need to give these little chaps a visit because you are bound to come across them sooner or later.

All these two extra classifications represent are oversize versions of the standard A sizes which we’ve been talking about. The reason printers use them is that the larger size allows for bleed and trim marks – all of which are trimmed off before your job is packed up and despatched.

And if you really want to get techie about them, RA0 has an area of 1.05 square metres and SRA0 an area of 1.15 square metres


Envelope Sizes


Now, on to Envelope sizes

If you’re that way inclined, there are a number of learning resources out there which delve in to mathematical relation to paper’s A sizes. But it does get rather complicated and I want to keep things straightforward and of practical use for you.

As you can see from the Envelope size chart below, and just like paper sizes, envelopes are sized so that each size up is double the previous one. 

If you compare the two charts, you’ll also see that the C sizes are just a little bigger than the corresponding A sizes. And there’s a very good reason for this because it allows a sheet of paper to fit neatly and easily in to the envelope with a millimetre or two to spare. 


C0 917 x 1297 mm

C1 648 x 917 mm

C2 458 x 648 mm

C3 324 x 458 mm

C4 229 x 324 mm

C5 162 x 229 mm

C6 114 x 162 mm

C7 81 x 114 mm

C8 57 x 81 mm

C9 40 x 57 mm

C10 28 x 40 mm

C11 22 x 32 mm

C12 16 x 22 mm


Ok, a quick test for the eagle-eyed: did you spot the omission?

You got it. There’s no DL size listed because it actually sits outside the C Classification. DL stands for Dimension Lengthways by the way.

It’s most common use is to enclose an A4 sheet which has been folded to 1/3rd A4.


But for now, let’s get back to the C sizes.

The fact that an A4 sheet fits in to a C4 envelope is easy to see. But look carefully and you’ll spot that an “A” size sheet, when folded in half, will fit neatly in to the next envelope size down.

For example, an A4 sheet folded in half fits in to a C5 envelope. And so on.


So, that’s about it with Paper and Envelope sizes and I hope this quick run-through has been helpful … and thanks for dropping in,


But before you go …

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