What Is Meant By Megabytes?

The term "megabyte" is ambiguous because it is commonly used to mean either 1000² bytes or 1024² bytes. The confusion originated as compromise technical jargon for the byte multiples that needed to be expressed by the powers of 2 but lacked a convenient name. As 1024 (2¹⁰) approximates 1000 (10³),
roughly corresponding SI multiples began to be used for binary
multiples.

One byte is 8 bits (binary digits), one kilobyte is 1024 bytes, one megabyte is 1024 kilobytes.