#9 envelope size
#9 Envelope Size: 98.425 × 225.425 mm, with inch and cm dimensions. Check proportions and common uses. Find the largest square for a paper craft.
- Millimetres
- 98.425 × 225.425 mm
- Centimetres
- 9.8425 × 22.5425 cm
- Inches · rounded to 4 decimals
- 3.875 × 8.875 in
- Aspect ratio · width:height
- 31:71 (1:2.29)
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
A small reply sheet or return form fits inside. A No. 9 envelope can itself fit inside a No. 10 envelope.
How it compares
No. 7¾ (Monarch) envelope is smaller in area. No. 10 (Commercial) 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 98.425 × 98.425 mm (3.875 × 3.875 in). Fold one short edge against a long edge so their corners meet. Crease the diagonal, cut off the extra 127 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.