Both Megabyte (MB) and Mebibyte
(MiB) are units of information or computer storage. But MB is used in two ways
either as equivalent to 1000 Kb or 1024 Kb. This creates some sort of
confusion. To avoid this, the International Electrotechnical Commission (IEC)
(1998), the leading international organization for worldwide standardization in
electrotechnology, approved as an IEC International Standard names and symbols
for prefixes for binary multiples for use in the fields of data processing and
data transmission. They recommended the use of Mebibyte (a combination of Mega and Binary) MiB, which always refer to 1024 Kb. See the table for percentage difference in storage
size in MB and MiB. The difference is significant as the storage size
increases.
Megabyte vs Mebibyte
Megabyte

Mebibyte

Megabyte
is a multiple of 1000

Mebibyte
is a multiple of 1024

The
unit symbol for the megabyte is MB

The
unit symbol for the mebibyte is MiB

Megabyte
is estimated as 10^6 or 1,000,000 bytes

Mebibyte
is exactly 1,048,576 bytes.

The
decimal prefix Mega means 1000 x 1000 bytes=100000 bytes

The
binary prefix Mebi means 2^{20}=bytes=1024 x 1024 bytes=1048576 bytes

1
MB=1000*1000 bytes= 1000000 bytes or 1000Kb

1
MiB=1024*1024 bytes= 1048576 bytes or 1048.576 Kb

Technically,
Megabyte is a power of 10

Mebibyte
is always a power of 2

Sometime1
MB refers to both 1000 Kb or 1024 Kb

1
MiB is always 1024 Kb

Disk
manufactures commonly use decimal prefix or MB

Memory
manufactures commonly use binary prefix or MiB.

Storage
devices such as HDDs and Flash drives, still uses MB (1000Kb) for calculating
storage size

Most
operating systems Ubuntu and Windows use mebibytes to report file and storage
sizes. For Example, 500 GB drive is reported by the OS as "465.66
GB" (meaning 465.66 GiB).
