A bit is the smallest unit of data. A bit is short for “binary digit,” because it can only be expressed as a 1 or a 0 (or a yes/no, or on/off). 8 Bits are a byte, and 1024 bytes are a kilobyte (kB). Here's where it can get a little confusing. We normally measure things in base ten, better known as the metric system, so you would expect a kilobyte to be 1,000 bytes. Unfortunately, it's not. In smaller numbers, the discrepancy between 1,000 and 1,024 is small enough to round off, but as we get into larger orders of magnitude, the difference can be appreciable. In 1998, a governing body called the International Electrotechnical Commission (IEC) declared that one billion bytes is one gigabyte. It hasn't really caught on, but the IEC made a new scale of “kibibytes (KiB)” and “mebibytes (MiB)” measured in base 1024. Memory storage, such as hard drives and optical disks, go by base ten; processing power and RAM go by base 1024, but use the older (now technically incorrect) nomenclature.

Memory Storage Scale
1000 Bytes=1 Kilobyte (kB)
1000 Kilobytes=1 Megabyte (MB)
1000 Megabytes=1 Gigabyte (GB)
1000 Gigabytes=1 Terabyte (TB)
1000 Terabytes=1 Petabyte (PB)
1000 Petabytes=1 Exabyte (EB)
1000 Exabytes=1 Zettabyte (ZB)
1000 Zettabytes=1 Yottabyte (YB)

Computer Processing and RAM Scale, common vernacular
1024 Bytes=1 Kilobyte
1024 Kilobytes=1 Megabyte
1024 Megabytes=1 Gigabyte
1024 Gigabytes=1 Terabyte
1024 Terabytes=1 Petabyte
1024 Petabytes=1 Exabyte
1024 Exabytes=1 Zettabyte
1024 Zettabytes=1 Yottabyte

Computer Processing and RAM scale, IEC standard
1024 Bytes=1 Kibibyte (KiB)
1024 Kibibytes=1 Mebibyte (MiB)
1024 Mebibytes=1 Gibibyte (GiB)
1024 Gibibytes=1 Tebibyte (TiB)
1024 Tebibytes=1 Pebibyte (PiB)
1024 Pebibytes=1 Exbibyte (EiB)
1024 Exbibytes=1 Zebibyte (ZiB)
1024 Zebibytes=1 Yobibyte (YiB)