When matching envelopes to cards it is important to find an envelope that is larger than and not the same size as the invitation card. Therefore the best size envelope to fit a 5 x 7 invitation would be our A7, 5 1/4 x 7 1/4 size envelopes. This envelope will give the appropriate amount of room left to right and top to bottom.
We do not have the exact weight of this card / envelope combination. If you only insert the one card inside the envelope it should be less than 1oz therefore would not incur extra postage. We usually advise customers to take 1 completed sample to the post office to have them determine if extra postage is required. We also encourage customers to have their invitations hand cancelled to prevent damage from the automated postal sorters. Here is a short article on What Hand Cancel Means
The standard A7 size is 5 1/8 x 7 inches.
The A7 size card is the most common size for invitations at LCI Paper. As a flat size or note style A7 has just the right amount of room to print most of your invitation details.
The only difference between an A7 flat card & fold card is the format (sometimes weight). In both instance the finished size is 5 1/8 x 7 (5 x 7). This would be the finished size for a flat card and a folder would fold down to 5 1/8 x 7. The style you get is personal preference.