The human appendix typically measures about 8 to 10 centimeters (approximately 3.1 to 3.9 inches) in length, but it can range from as short as 2 centimeters to as long as 20 centimeters or even more in rare cases. Its diameter is usually between 7 and 8 millimeters, roughly the width of a pencil or smaller than 1.3 centimeters (about the width of a pinky finger).

Summary of Appendix Size

• Average length: 8 to 10 cm (3.1 to 3.9 in)
• Length range: About 2 to 20 cm (possible up to 23.5 cm in exceptional cases)
• Diameter: Typically 7 to 8 mm (0.7 to 0.8 cm)

This size corresponds to a small, narrow, tubular structure located in the lower right abdomen connected to the large intestine.