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Category Code Utilities

Input Hexadecimal (Big Endian)

Word Size (Swap Boundary)

Output Formatting Space between bytes Add 0x prefix to words

Output Hexadecimal (Little Endian)

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About

When transmitting multi-byte data architectures across networks or interfacing between different microprocessors, the order in which bytes are stored - known as endianness - becomes a critical point of failure. Big Endian (often used in network protocols) stores the most significant byte (MSB) at the lowest memory address, whereas Little Endian (standard in x86/x64 processors) stores the least significant byte (LSB) at the lowest address. Misinterpreting this sequence results in profound data corruption.

This tool strictly transposes the hexadecimal byte sequence according to a specified N-bit word boundary. It automatically handles byte-alignment, ensures even-length parity, and reverses the atomic 8-bit pairs without altering the internal nibble structure of the bytes themselves. This guarantees bit-perfect translation between architectures.

Formulas

Endian conversion is a discrete transposition of bytes within a fixed word boundary. A single byte consists of 2 hexadecimal characters (8 bits). The algorithm does not reverse the characters individually, but rather reverses the sequence of the byte pairs.

Let word W consist of k bytes: B₀, B₁, ..., B_k−1.
The transposed Little Endian word W′ is ordered as:

W′ = B_k−1, B_k−2, ..., B₀

Example (32-bit Word = 4 Bytes):
If W = 0A 1B 2C 3D
Then W′ = 3D 2C 1B 0A

Reference Data

Architecture / Protocol	Standard Endianness	Common Use Cases
x86 / x64 (Intel & AMD)	Little Endian	Modern desktop and server processors, Windows OS.
ARM (Bi-endian)	Little Endian (Default)	Mobile devices, Apple Silicon, embedded systems.
Network TCP/IP	Big Endian	IP headers, packet routing, standard network byte order.
Motorola 68000 / PowerPC	Big Endian	Legacy Apple hardware, IBM mainframes, enterprise routers.
Java Virtual Machine (JVM)	Big Endian	Internal bytecode representation and `DataInputStream`.
WebAssembly (Wasm)	Little Endian	In-browser high-performance memory execution.
RISC-V	Little Endian	Modern open-standard instruction set architecture.
JPEG / EXIF Data	Big Endian	Image headers and metadata markers.
BMP (Bitmap)	Little Endian	Standard uncompressed image file structure.
WAV (RIFF format)	Little Endian	Standard uncompressed audio file structure.

Frequently Asked Questions

Endianness applies to the specific data type (word) being processed. Swapping a 32-bit integer requires reversing 4 bytes at a time. If you have an array of two 16-bit integers and you swap them as a single 32-bit block, the result will be incorrect. The word size dictates the boundary for the reversal.

A valid byte requires exactly 2 hexadecimal characters (a high nibble and a low nibble). If your input has an odd number of characters (e.g., 'F3A'), the tool assumes a leading zero was omitted and prepends it (e.g., '0F3A') before processing.

No. Endianness swapping only changes the order of the bytes. It does not flip bits (like a NOT operation) nor does it reverse individual characters. For example, the byte "A1" remains "A1", but its position in the overall sequence moves.

Historically, early network protocols standardizing the ARPANET (which evolved into TCP/IP) chose Big Endian. This standardization ensures that computers with differing internal architectures can reliably parse packet headers (like IP addresses and ports) by agreeing on a universal transmission sequence.