Not every greeting card needs to open. A standard greeting card skips the center fold that defines a traditional card and stays flat — a single rigid panel printed on the front, the back, or both, closer in construction to a heavy postcard than a booklet. That difference in construction changes what the format is good for: without a fold to worry about, the card can be handled and mailed like a postcard, and the message has to work within one panel rather than being spread across an interior spread. Because there's no fold to reinforce, cardstock weight is what gives a flat card its structure and feel. A 14 pt to 16 pt stock is a reasonable starting point, giving the card enough rigidity to resist bending in the mail or in a stack, while a heavier 18 pt to 32 pt stock reads as noticeably more substantial — worth considering for a card meant to double as a keepsake, like a save-the-date or an announcement people are likely to display rather than discard. Since the entire card is a single flat sheet, the front and back can both carry full-bleed printing without needing to account for how a design will look once folded, which gives a bit more design freedom than a folded card offers. Finish options work the same way they would on any printed card: a gloss laminate for vibrant color and shine, a matte or soft-touch laminate for a more restrained, contemporary look, or an uncoated stock if part of the back is meant to be written on. Rounded corners are a common upgrade on flat cards specifically, since the format's simplicity makes small finishing touches — a corner treatment, a subtle emboss, a foil accent on the front — more noticeable than they might be on a card that's already visually broken up by a fold. Standard flat cards suit a specific set of use cases well: announcements, postcard-style greetings, save-the-dates, or any message short enough to fit on one surface without needing an interior for elaboration. For a message that benefits from more space — a longer note, a multi-part design, or anything meant to be opened as a small reveal — a folded card remains the better fit. Matching envelopes, sized precisely to the flat card's dimensions, are typically included so the finished piece is ready to address and mail without any extra sourcing.