DVD-RW is a rewritable optical disc format with equal storage capacity to a DVD-R, typically 4.7 GB. It was developed by Pioneer in 1999. Standard DVD-RW discs are 120mm, but Mini DVD-RW discs are available with a diameter of 80mm and a capacity of 1.46 GB.
It is claimed that DVD-RW discs may be written to about 1,000 times before needing replacement, and are often used for computer backups and DVD video recorders.
DVD-RW competes with DVD+RW, and many recorders can use both formats.
The recording layer in DVD-RW and DVD+RW is not an organic dye, but a special phase change metal alloy, often GeSbTe. The alloy can be switched back and forth between a crystalline phase and an amorphous phase, changing the reflectivity.
A specification for dual-layer DVD-RW discs with a capacity of 8.5 GB was approved by the DVD Forum, but were not released due to cost and competition from higher-capacity formats like Blu-ray and HD DVD-R.