The length of a cigar is measured in inches and the diameter in ring gauge. The diameter in inches of a cigar equals its ring gauge divided by 64. 

Example:

Large ring gauge cigars contain more tobacco and possibly a larger combination of different types of leaves than small ring gauge cigars, so they will have a more complex flavor and produce more smoke in comparison. The most popular sizes are: Panatela, Corona, Lonsdale, Robusto, Churchill and Double Corona. The exact sizes will vary from brand to brand.

According to their shape, cigars can be classified in two basic categories: Parejos, cigars with straight sides, rounded heads and open foots; and Figurados, cigars with irregular sides or cigars that are very difficult to make. Some of the most popular Figurado shapes are: Belicoso, Pyramids, Torpedo, Perfecto and Diademas.