Capacity may refer to any of the following:
1. When referring to a drive, capacity or storage capacity is the maximum amount of data a device such as a hard drive can hold. For example, if you have a 200 GB hard drive, it has a total capacity of 200 GB, but if you had 150 GB of installed programs it has 50 GB of free space. When a device reaches its capacity, it cannot hold any more information. In the example below, you can see the Primary Drive (C:) has 39.1 GB available.
2. When referring to anything that holds a charge, capacity is the maximum amount of power the device is capable of holding.