What is the size of A3 paper compare to A4?

Two A4 papers side by side make an A3 paper. That’s mean A3 paper size is double the size of A4.

So the size of A3 paper in cm is: 297 x 420

The size of A3 in inches is: 11.7 x 16.5

A3 is the big paper we use in copiers. Few home printers can handle A3. If we fold an A3 paper then we have an A4 two sheet (four pages) brochure.

Be careful: when we say that A3 is double the A4 we don’t mean that it is both double the width and double the height. That makes 4 times an A4, equal to A2 paper. The image above describes this well.