Endianness Swap Calculator

About this calculator

Endianness describes the byte order a system uses to store multi-byte values: big-endian stores the most significant byte first (this is “network byte order,” used in TCP/IP headers), while little-endian stores the least significant byte first (native to x86/x86-64 and most ARM configurations). Swapping means reversing the byte sequence — 0x12345678 becomes 0x78563412 — while the underlying decimal value only matches one interpretation or the other.

Network and embedded/firmware engineers hit this constantly when reading a packet capture, a binary file format, or register dumps from mixed-endian systems, since misreading the byte order silently produces a completely wrong number rather than an obvious error.