14. What are the sizes and storage capacities of DVD ?

DVD media are available in two physical sizes: standard 12 cm (4.7 inches) and mini 8 cm (3.1 inches), both 1.2 mm thick, made of two 0.6mm substrates glued together. These are the same form factors as a standard or mini CD. A DVD disc can be manufactured as a single-sided or double-sided disc. Each side can have one or two layers of data. In general, a standard 12-cm, single-sided DVD can hold 4.7 GB with single layer, and 8.5 GB with dual layer. The smaller 8-cm single-sided DVD can hold 1.4 GB with single layer, and 2.47 GB with dual layer.

The capacity is doubled for double-sided discs. A disc can also have mixed layers, one side is single layer while the other side is dual layer. Formatted DVD-RAM discs have slightly less than the stated above capacity. Note that the notation GB here is misleading in the sense that it is billions of bytes (1000*1000*1000), not the standard gigabytes (1024*1024*1024) commonly used to describe desktop hard drive storage capacities.

The following table shows popular DVD sizes and storage capacities.

Standard	Size	Capacity	Format	Side/Layer
DVD-5	12 cm	4.7 GB	DVD+R/RW, DVD-R/RW	SS,SL
	8 cm	1.4 GB	DVD+R/RW, DVD-R/RW	SS,SL
DVD-9	12 cm	8.5 GB	DVD+R DL, DVD-R DL	SS,DL
DVD-10	12 cm	8.75 GB	DVD+R/RW, DVD-R/RW	DS,SL
DVD-18	12 cm	15.9 GB	DVD+R	DS,DL

SS (Single-Sided)
DS (Double-Sided)
SL (Single-Layer)
DL (Dual-Layer or Double-Layer)