Card and Envelope Sizing Chart Envelope Size – 2-5/16” x 3-5/8” - Card Paper Size - 3-3/8” x 4-3/8” (Card folded in half – 2-1/4” x 3-3/8”) Envelope Size – 2-5/16” x 6” – Card Paper Size – 4-7/8” x 5-3/4” (Card folded in half – 2-1/8” x 5-3/4”) Envelope Size – 3” x 3” – Card Paper Size – 2-3/4” x 5-1/2” (Card folded in half – 2-3/4” x 2-3/4”) Envelope Size – 3-5/8” x 5-1/8” – Card Paper Size – 4-7/8” x 7” (Card Folded in half – 3-1/2” x 4-7/8”) Standard Envelope size 3-5/8” x 6-1/2” can be used and bought in bulk Envelope Size – 4” x 4” – Card Paper Size – 3-3/4” x 7-1/2” (Card folded in half – 3-3/4” x 3-3/4”) Envelope Size – 4-1/8” x 9-1/2” – Card Paper Size 8” x 9-1/4” (Card folded in half – 4” x 9-1/4”) This is a standard #10 business envelope that can be bought in bulk. A2 Envelope Size – 4-3/8” x 5-3/4” – Card Paper Size – 5-1/2” x 8-1/2” (Card folded in half – 4-1/4” x 5-1/2”) A4 Envelope Size – 4-3/4 x 6-1/4 – Card Paper Size – 8” x 12-1/4” (Card folded in half – 4-1/2” x 6-1/8”) A6 Envelope Size – 4-3/4” x 6-1/2” – Card Paper Size – 9-1/4” x 6-1/4” (Card folded in half – 4-5/8” x 6-1/4”) A7 Envelope Size – 5-1/4” x 7-1/4” – Card Paper Size – 7” x 10” (Card folded in half – 5” x 7”) A9 Envelope Size – 5-5/8” x 8-5/8” – Card Paper Size – 8-1/2” x 11” (Card folded in half – 5-1/2” x 8-1/2”) For the A9 Envelope – you can use a standard 6” x 9” envelope and it buy in bulk