United States reference
US announcement A-names are envelope names measured in inches. They are not ISO A-series paper sizes, even when the label looks identical.
Nominal size reference
Every table uses nominal exterior width × height. International sizes lead with millimetres; US sizes lead with conventional fractional inches.
| Format | Native size (width × height) | Converted size (width × height) | Source checked | Context |
|---|---|---|---|---|
| A1 / 4-barUS announcement | 3 5/8 × 5 1/8 in3.625 × 5.125 in decimal | 92.07 × 130.17 mm | Neenah Paper ↗27 August 2026 | open side |
| A2 announcementUS announcement | 4 3/8 × 5 3/4 in4.375 × 5.75 in decimal | 111.13 × 146.05 mm | Neenah Paper ↗27 August 2026 | open side |
| A6 announcementUS announcement | 4 3/4 × 6 1/2 in4.75 × 6.5 in decimal | 120.65 × 165.1 mm | Neenah Paper ↗27 August 2026 | 4 1/2 × 6 1/4 inch card |
| A7 invitationUS announcement | 5 1/4 × 7 1/4 in5.25 × 7.25 in decimal | 133.35 × 184.15 mm | Neenah Paper ↗27 August 2026 | 5 × 7 inch card or photo |
| A9 announcementUS announcement | 5 3/4 × 8 3/4 in5.75 × 8.75 in decimal | 146.05 × 222.25 mm | Neenah Paper ↗27 August 2026 | open side |
A7 commonly means a 5 1/4 × 7 1/4 inch invitation envelope in the United States, while ISO A7 paper is 74 × 105 mm. A6 has the same kind of conflict.
Nominal envelope dimensions describe the exterior format, not guaranteed usable internal space. Seams, lining, stock thickness, multiple pieces and manufacturing tolerances reduce practical room; sample before a bulk order or print run.
Invitation stock, layered cards, photographs, ribbon and embellishment usually need more working room than a single thin sheet.
Start from the finished card or photo size and choose a practical per-edge clearance. Borderline results remain visibly separated from comfortable candidates.