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Big Endian vs Little Endian: Understanding Byte Order in Computing

Anastasios Antoniadis

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Explore the fundamental concepts of Big Endian and Little Endian byte orders in computing, their implications on cross-platform compatibility, network protocols, performance, and data serialization. This article provides a deep dive into understanding endianness, its impact on software development, and strategies for managing byte order differences effectively.

BIG endian vs. Little Endian

Endianness, in computing, refers to how bytes are ordered in memory. This seemingly small aspect of computer architecture is actually quite important for developers, especially when working with low-level programming, data serialization, network protocols, and systems integration. There are two primary byte order conventions – Big Endian and Little Endian. It’s crucial for developers to understand the differences between these conventions, their implications, and where they are applied, in order to navigate the complexities of cross-platform and networked application development.

What are Big Endian and Little Endian?

Endianness dictates how multi-byte data types, such as integers and floating points, are stored in memory. The distinction lies in which end, or “byte”, of the data type is stored first – the “big end” or the “little end”.

Big Endian

In Big Endian format, the most significant byte (MSB) – the “big end” of the number – is stored at the smallest memory address, and the remaining bytes follow in decreasing significance. This convention is akin to how humans typically write and read numbers; for example, the number 0x12345678 would be stored in memory as:

Memory Address    Value
...               ...
0x01              0x12
0x02              0x34
0x03              0x56
0x04              0x78
...               ...

Little Endian

Conversely, Little Endian format stores the least significant byte (LSB) – the “little end” – at the smallest memory address, with the bytes following in increasing significance. Using the same example number 0x12345678, it would be stored in memory as:

Memory Address    Value
...               ...
0x01              0x78
0x02              0x56
0x03              0x34
0x04              0x12
...               ...

Implications of Endianness

The choice between Big Endian and Little Endian affects several areas in computing:

Cross-Platform Compatibility

Different computer architectures adopt different endianness conventions. For instance, ARM architectures can be configured as either, while x86 architectures are predominantly Little Endian, and many older architectures, like IBM’s z/Architecture, are Big Endian. This variance necessitates careful handling of data when transferring between systems of differing endianness to avoid corruption or misinterpretation.

Network Protocols

The Internet Protocol suite (TCP/IP), which forms the backbone of data exchange over the internet, specifies Big Endian as the standard byte order for transmitting numerical values in protocol headers. Consequently, systems that use Little Endian must convert these values to Big Endian before sending them over the network – a process known as “network byte order” conversion.


The choice of endianness can also have performance implications. Some argue that Little Endian systems have an edge in arithmetic operations, as they can begin operations on the LSB without waiting for the rest of the data. However, the practical performance impact is often negligible compared to other system bottlenecks.

Data Serialization

In data serialization, where structured data is converted into a format suitable for storage or transmission, endianness plays a crucial role. Developers must ensure that data serialized on a system with one byte order can be correctly deserialized on a system with a different byte order.

Dealing with Endianness in Development

To manage endianness effectively, developers can use:

  • Endian Conversion Functions: Many programming languages and standard libraries provide functions to convert between Big and Little Endian formats.
  • Explicit Data Layouts: Some programming languages allow developers to explicitly define the byte order of data structures.
  • Endian-Agnostic Programming: Whenever possible, use high-level abstractions and data types that abstract away the underlying byte order, reducing the need to deal directly with endianness.


While often overlooked, the concept of endianness is a fundamental aspect of computer architecture that can have far-reaching implications in software development. By understanding the differences between Big Endian and Little Endian formats, developers can ensure data integrity and compatibility across diverse systems and networks. Whether working on low-level system programming, networked applications, or data serialization, a solid grasp of endianness and its practical considerations is essential for successful development in today’s interconnected computing landscape.

Anastasios Antoniadis
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