Paper size · ISO A
A3 paper size
A3 Paper Size: 297 × 420 mm, with inch and cm dimensions. Check proportions and common uses. Find the largest square for a paper craft.
297 × 420 mm11.6929 × 16.5354 inRatio 99:140 (1:1.414)
- Millimetres
- 297 × 420 mm
- Centimetres
- 29.7 × 42 cm
- Inches · rounded to 4 decimals
- 11.6929 × 16.5354 in
- Aspect ratio · width:height
- 99:140 (1:1.414)
Common uses
A3 gives diagrams, drawing studies and folded A4 booklets twice the area of A4.
How it compares
Two A3 sheets placed side by side make approximately one A2 sheet. Cut A3 across the middle of its long edge to get two A4 sheets. Whole-millimetre rounding can leave a 1 mm difference at a cut edge.
Cut a square for origami
The largest square from a flat rectangle this size is 297 × 297 mm (11.6929 × 11.6929 in). Fold one short edge against a long edge so their corners meet. Crease the diagonal, cut off the extra 123 mm strip, then open the triangle.
Try the beginner origami dog with your square, or see how to prepare square paper.