Bit is the smallest unit.

One Nibble = 4 bit.

One Byte = 8 bit.

One Kilobyte (KB) = 1,024 Byte.

One Megabyte (MB)  = 1,024 KB.

One  Gigabyte (GB)  = 1,024 MB.

One Terabyte (TB)  = 1,024 GB.

One Petabyte (PB) = 1,024 TB.

One  Exabyte (EB)  = 1,024 PB.

One Zetabyte (ZB) – 1,024 EB.

One  Yottabyte (YB) – 1,024 ZB.

One Brontebyte (BB) – 1,024 YB.

One Geopbyte – 1,024 BB.

A Geopbyte is the highest storage unit and it does not have any short form.