Paper size · US envelopes

A7 envelope size

A7 Envelope Size: 133.35 × 184.15 mm, with inch and cm dimensions. Check proportions and common uses. Find the largest square for a paper craft.

133.35 × 184.15 mm5.25 × 7.25 inRatio 21:29 (1:1.381)
Millimetres
133.35 × 184.15 mm
Centimetres
13.335 × 18.415 cm
Inches · rounded to 4 decimals
5.25 × 7.25 in
Aspect ratio · width:height
21:29 (1:1.381)
This sizeA4
A7 envelope and A4, at the same scale. Sheets shown with the short edge across.

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 holds a 5 × 7 inch card or photo. The envelope is larger than the card so it can slide in.

How it compares

A6 envelope is smaller in area. A8 envelope is larger in area. These formats have their own proportions; halving a sheet does not necessarily produce the next size.

From sheet to fold

Cut a square for origami

The largest square from a flat rectangle this size is 133.35 × 133.35 mm (5.25 × 5.25 in). Fold one short edge against a long edge so their corners meet. Crease the diagonal, cut off the extra 50.8 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.

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