Bandwidth is generally the amount of data that can be carried from one point to another in a given time period (usually a second). Bandwidth is often used as a synonym for data transfer rate. This kind of bandwidth is usually expressed in bits (of data) per second (bps). Occasionally, it's expressed as bytes per second (Bps). In most computer systems, a byte is a unit of data that is eight binary digits long. For example, one megabyte ("one million bytes") is actually 1,048,576 (decimal) bytes.
A kilobyte (KB) is 1024 bytes.
1024 bytes = 1 KB 1024 KB = 1 MB 1024 MB = 1 GB 1024 GB = 1 TB 1024 TB = 1
Use the bandwidth calculator and convert bytes, Kb, Mb and Gb to the size of the files you are storing and transferring.
Then calculate the costs of the data storage and transfer based on the amount of bytes. A hosting provider's charges are based on gigabytes of usage, so for example you might pay $0.25 for 1 GB of data transfer, this means you are paying $0.25 to transfer over 1 billion bytes of data (over 8 billion bits).