Mb vs. MiB

When measuring digital storage, two units of measurement are often used interchangeably: MB and MiB. However, these two units are not the same, and understanding their differences is important in ensuring accurate measurements. This article will explore the differences between MB and MiB, their origins, and their uses.

Origins of MB and MiB

The unit MB, or megabyte, is a standard digital storage unit that has been used since the early days of computing. It represents 1,000,000 bytes of storage, where a byte is the basic unit of information used in computing. The prefix “mega-” means “one million,” so a megabyte is literally one million bytes.

The unit MiB, or mebibyte, is a more recent addition to the computing world. It was introduced in 1998 by the International Electrotechnical Commission (IEC) as part of the International System of Units (SI). The prefix “mebi-” is derived from “mega binary,” and represents 1,048,576 bytes of storage, precisely 2^20 bytes.

Differences between MB and MiB

The main difference between MB and MiB is their size. As mentioned, a megabyte represents 1,000,000 bytes of storage, while a mebibyte represents 1,048,576. This means that one MiB is roughly 5% larger than one MB.

The reason for this difference is due to the way storage is calculated in computing. Computers use a binary system to store and process information, which means that data is stored in powers of two (2, 4, 8, 16, 32, 64, 128, etc.). This binary system is more efficient for computing than the decimal system used in everyday life.

However, when the metric system was established, it was based on the decimal system, which meant that the prefix “mega-” represented 1,000,000. This led to confusion when measuring digital storage, as a megabyte’s size differed from what many expected. To address this issue, the IEC introduced the mebibyte as a standard unit of measurement that—more accurately—reflects storage size in binary systems.

Uses of MB and MiB

MB is still widely used in computing and digital storage, mainly when dealing with storage devices such as hard drives, USB drives, and SD cards. It is also commonly used to measure the size of files, such as documents, images, and videos.

MiB is less commonly used in everyday computing but is essential for specific applications requiring precise measurements. For example, it is used to measure RAM (random access memory) in computers and data transfer rates for internet connections and other digital communication systems.


In conclusion, MB and MiB are both units of measurement used to measure digital storage, but they represent different sizes. MB represents 1,000,000 bytes of storage, while MiB represents 1,048,576. Understanding the differences between these units is important for accurate measurements in computing and digital storage, particularly in applications requiring precise measurements.

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