Why your internet speed is measured in bits while your files use bytes

Science · Published 20 October 2026 Swipe more like this →

In short: Data transfer rates are often expressed in bits per second, while storage is measured in bytes. This distinction matters because one byte contains eight bits. When your service provider advertises a one megabit connection, they are promising one million bits per second, which translates to only one-eighth of that in megabytes.

In the world of telecommunications, data rates quantify how quickly information moves through a system. These rates are typically measured in bits per second or bytes per second. A bit is the fundamental unit of data, while a byte—often synonymous with an octet—consists of exactly eight bits. This numerical relationship is the primary reason for the confusion many users face when comparing advertised connection speeds with actual file download times. When a connection is marketed as one megabit per second, it represents one million bits per second. To convert this to megabytes per second, one must divide by eight, resulting in 0.125 megabytes per second.

The confusion is further complicated by the use of prefixes. Traditionally, prefixes like kilo and mega were used to denote powers of ten, consistent with the International System of Units. However, in computing, these terms were frequently used to represent powers of two, where a kilo often meant 1,024 instead of 1,000. To resolve this ambiguity, the International Electrotechnical Commission introduced specific binary prefixes in 1998, such as kibi and mebi, to explicitly denote powers of two. For instance, a mebibyte represents 1,048,576 bytes, whereas a megabyte strictly refers to one million bytes.

Despite these formal standards, industry practice remains inconsistent. While data transfer rates typically adhere to decimal prefixes, the historical habit of using binary-based abbreviations persists. The Institute of Electrical and Electronics Engineers reaffirmed standards like IEEE 1541-2002 to clarify these definitions, yet the common usage of symbols like Mbps or KBps often ignores these distinctions. Understanding whether a measurement refers to bits or bytes, and whether it follows decimal or binary scaling, is essential for accurately interpreting technical specifications. This nuance ensures that users can distinguish between raw transmission capacity and actual data storage volume, preventing common misunderstandings regarding network performance and hardware capacity.

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