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What Print Size is 'A3' or 'A4'?

Ray . , Nov 30, 2003; 02:44 p.m.

I keep seeing this reference, and can't find an answer in the archives. What size in inches is an A3 or A4 print? Or A2, for that matter?

Or is this a reference to digital print sizes?

Thanks in advance.


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Mike ( Lab Monkey) , Nov 30, 2003; 02:50 p.m.

A4 is 11x14.

I'm not sure what the others are.

Ivar Wind Skovgaard , Nov 30, 2003; 03:08 p.m.

International Standard Paper Sizes - A4 is approximately 8.3x11.7 inches.

Marcelo Porto , Nov 30, 2003; 03:34 p.m.

The 'A' series is the standard paper sizes defined by ISO - International Standards Organisation (originally created by DIN, the German Industry standards) - and adopted by all countries using the metric system, ie, the rest of the world except the US. Those are the ´de facto´standard for almost everything that is printed in those countries, as well as stationery, envelopes, business cards, etc.

As defined in the norm, every size is exactly one half of the precedent, starting with the A0 (841 × 1189 mm) and dividing along the long size. The proportions between the sides is always one to square root of two (1:1.4142...), which corresponds to the relationship between the side of a square and its diagonal. About the sizes you've asked:

A2 = 594 x 420 mm A3 = 420 x 297 mm A4 = 297 x 210 mm A5 = 210 x 148 mm, etc.

Those sizes existed for a long time, but for photography they were relatively unimportant before digital - probably because of Kodak, photo lab used metric approximations of the American sizes - 4 x 6 inches = 10 x 15 cm, etc. With people printing their copies from home printers, the standard paper sizes became important, because the printers are designed to use them!

If you are interested, there is an excellent site at:


Rgds, Marcelo

John Stockdale , Dec 01, 2003; 05:36 a.m.

A0 is theoretically exactly a square metre. Every size under is a half,quarter,...etc (in area, that is, hence the 1.414 factor mentioned above for the lengths)

There is a B series as well, with different proportions. But it's not so common. And a C series too, if I remember correctly.

Off Topic: The metre, incidentally, was defined in Napoleon's day as one 10,000,000th of the distance from the North Pole through Paris to the equator. The idea apparently was to remove units of measurements from temporal and parochial things like the foot being the supposed length of the king's foot. It's not very helpful really, except it's easy to remember the circumference of the Earth is 40,000km.

gareth harper , Dec 01, 2003; 01:10 p.m.

A4 is standard document size 8 1/4 inch by 11 3/4 inch.

A3, off the top of my head is near enougth 12x16 inch.

In the UK standard print sizes are 10x8, 12x16 and 20x16. A4 has rapidly become a standard size as a result of inkjets I think.

Sizes like 11x14 are hard to come by in the UK.

Russell Brooks , Dec 01, 2003; 03:07 p.m.

I'm in Europe and I've hiz upon the 9 1/2 x 12 inch papers. Normally I like to print 8x12 but printing 11 x 7.5 is working out well. And the benefit is that the paper is smaller and thus easier to deal with shuttling around the darkroom...

Roger Hicks , Dec 04, 2003; 04:27 p.m.

Dear Ray,

All A-series sizes are halvable, thanks to the format of 1:square root 2. Thus A4 is 210x297mm, A3 420x297mm, A2 420x594mm, A1 840x594mm, A0 (one square metre) 840 x 1088mm -- all figures from memory, but pretty close. For those not acquainted with the metric system: now is the time to march proudly forward into the late 18th century.



Mark Farnsworth , Dec 04, 2003; 04:36 p.m.

(Edited) The "A" series of paper sizes has nothing to do with the metric system. If it did, the paper sizes would be in multiples of 10 or 100. The square root of 2 has absolutely nothing to do with the metric system.

Ivar Wind Skovgaard , Dec 05, 2003; 02:15 a.m.

Mark, you might want to check the definition af the A series before rushing to conclusions...

As should be obvious to anyone acquainted with photographic apertures, the square root of two is hard to avoid when dealing with areas in a consistent and scalable manner.

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