How big is an A4 sheet of paper?

An A4 sheet of paper measures 210 millimeters in width by 297 millimeters in length. In inches, this is equivalent to approximately 8.27 inches by 11.69 inches. Measurements for A4 paper are defined under ISO 216, an international sizing standard.

The ISO 216 paper sizing system is standard in most countries around the world. Although ISO 216 paper sizes are available in the United States, they are not in wide use.

The ISO 216 system includes two paper formats, known as A and B Series, respectively, as well as an envelope format, known as C Series. There are 11 different paper sizes in both the A Series and the B Series.