Endian Converter

This tool reverses the byte order of a multi-byte hexadecimal value to convert between big-endian (most significant byte first) and little-endian (least significant byte first) representations. It does not alter the numeric value—only its byte sequence—making it essential for interpreting raw data across architectures and protocols.

You’ll need it when interfacing microcontrollers with peripherals via I²C, SPI, or UART where byte ordering differs (e.g., reading a 32-bit ADC register on an ARM MCU that expects LE but a sensor transmits BE). It’s also critical for firmware debugging, memory dump analysis, and binary protocol decoding.

The input is styled as a type="number" for UI consistency, but the underlying JavaScript logic parses the value as a hexadecimal string. Always enter uppercase hex digits (e.g., AABBCCDD) without prefixes (0x). Invalid characters will result in undefined behavior—so double-check formatting before calculating.

“From Endian” specifies the current byte order of your input value: 1 means your hex string is in big-endian format (MSB first), and 0 means it’s already little-endian (LSB first). The tool converts *from* that format *to* the opposite endian—so set it based on your source data’s native ordering.

The tool supports any positive integer byte count (e.g., 1, 2, 4, 8), but practical use cases are typically 2 (16-bit), 4 (32-bit), or 8 (64-bit) for common data types. The byte count determines how many bytes are grouped and reversed—entering too few bytes truncates; too many pads or causes parsing errors if input length mismatches.

That’s correct: big-endian AABBCCDD stores the most significant byte first (AA), while little-endian stores the least significant byte first (DD). Reversing all four bytes yields DDCCBBAA—the exact same 32-bit value, just reordered per LE convention.

No—it performs pure byte-order reversal without interpreting sign bits or IEEE-754 structure. For signed two’s complement values, the conversion is still valid, but you must manually handle sign extension or reinterpretation afterward. For floats, ensure both systems use identical IEEE-754 formats before swapping endianness.

Network byte order is standardized as big-endian (e.g., TCP/IP headers, DNS packets). When a little-endian device (like most x86 or ARM hosts) sends multi-byte data over the network, it must convert to big-endian first—this tool helps verify or generate those converted values during protocol implementation or packet analysis.

The tool assumes left-zero-padding: e.g., entering FF with Byte Count = 4 treats it as 000000FF (BE) or FF000000 (LE), depending on the “From Endian” setting. Always validate that your input length matches expectations—or pad explicitly to avoid unintended interpretation.

Yes—this tool reverses *byte order*, not bit order. For example, 0x1234 (2 bytes) becomes 0x3412, not 0x2C48 (which would be bit-reversed). Bit reversal is used in FFTs or CRCs; byte reversal is for cross-architecture data alignment—confusing them leads to corrupted protocol data.