9 × 12 envelope size
9 × 12 Envelope: 228.6 × 304.8 mm, with inch and cm dimensions. Check proportions and common uses. Find the largest square for a paper craft.
- Millimetres
- 228.6 × 304.8 mm
- Centimetres
- 22.86 × 30.48 cm
- Inches · rounded to 4 decimals
- 9 × 12 in
- Aspect ratio · width:height
- 3:4 (1:1.333)
Common uses
Choose an envelope with space around the contents, especially for several sheets or a thick card. The dimensions describe the closed envelope, excluding its flap.
What it holds
It takes an 8.5 × 11 inch Letter sheet flat, without a fold.
How it compares
6x9 catalog envelope is smaller in area. 10x13 catalog envelope is larger in area. These formats have their own proportions; halving a sheet does not necessarily produce the next size.
Cut a square for origami
The largest square from a flat rectangle this size is 228.6 × 228.6 mm (9 × 9 in). Fold one short edge against a long edge so their corners meet. Crease the diagonal, cut off the extra 76.2 mm strip, then open the triangle.
These are the closed envelope dimensions. For an actual envelope, open the seams first and measure the usable flat paper before cutting. Try the beginner origami dog with your square, or see how to prepare square paper.