A4 is a standard paper size format that measures 21cm (210mm) by 29.7cm (297 mm). In inches, A4 paper size measures 8.3 inches by 11.7 inches.
Cutting it in half will create two A5 sheets of paper. An A4 piece of paper will fit into a C4 envelope. When folded in half, it will fit into a C5 envelope. A4 is part of the A series and is defined by the ISO 216 international paper size standard. [1]
Reference(s)
- Papersizes.io.”A4 Paper Size Dimensions” Retrieved 2026-01-26 https://papersizes.io/a/a4.