Question: what is the standard invitation size?
Answer: Custom wedding invitations can cause problems when it comes to finding matching envelope sizes, which is why they are often found in sizes A6 (4 3/4" x 6 1/2"), A7 (5 1/4" x 7 1/4"), A8 (5 1/2" x 8 1/8") and A9 (5 3/4" x 8 3/4"). You may also see sizes C0 to C10 and A10.