About

Bit ordering errors cause silent data corruption. A reversed byte in a network packet, a swapped nibble in an embedded register, or a wrong-endian integer in a file header can produce results that look plausible but are entirely wrong. This tool performs exact bitwise reversal on arbitrary binary data. It operates in three modes: full-stream reversal (all bits treated as one sequence), per-byte reversal (each 8-bit group reversed independently), and byte-order reversal (endianness swap without touching bit order within bytes). Input accepts raw binary strings, hexadecimal, decimal integers, or plain ASCII text. The output is computed via direct string manipulation on the canonical binary representation. No approximation occurs. The tool assumes unsigned integers and zero-pads to 8-bit boundaries when operating in byte-aware modes.

Limitations: maximum input length is 10,000 characters in any format. Negative integers are not supported directly. Feed two's complement binary manually if needed. For multi-byte ASCII, each character maps to its 8-bit code point (0 - 127). Extended Unicode above U+00FF is encoded as 16-bit units.

Formulas

Binary reversal is a deterministic string transformation. Given an input value converted to its canonical binary string B of length n, the three reversal modes are defined as follows:

Full-Stream Reversal: For binary string B = b₀b₁…b_n−1, the reversed output B′ is:

B′ = b_n−1b_n−2…b₀

Per-Byte Reversal: The binary string is zero-padded to a multiple of 8 bits, then split into bytes B₀, B₁, …, B_k. Each byte is reversed independently:

B_i′ = reverse(B_i) for i = 0, 1, …, k

Byte-Order Reversal (Endianness Swap): Bytes are reordered without modifying internal bit order:

B′ = B_k B_k−1 … B₀

Where B = binary string, n = total bit count, b_i = individual bit at index i, k = number of bytes − 1, and reverse() denotes string reversal. Format conversions use standard positional notation: binary to decimal via n−1∑i=0 b_i ⋅ 2ⁿ⁻¹⁻ⁱ, and hex via 4-bit nibble grouping.

Reference Data

Input Format	Example Input	Binary Equivalent	Full Reverse	Per-Byte Reverse	Byte-Order Reverse
Binary	10110010	10110010	01001101	01001101	10110010
Binary (16-bit)	10110010 01001101	1011001001001101	1011001001001101	01001101 10110010	01001101 10110010
Hex	B2	10110010	01001101	01001101	10110010
Hex (16-bit)	B2 4D	1011001001001101	1011001001001101	01001101 10110010	01001101 10110010
Decimal	178	10110010	01001101	01001101	10110010
Decimal	45645	1011001001001101	1011001001001101	01001101 10110010	01001101 10110010
ASCII	A	01000001	10000010	10000010	01000001
ASCII	Hi	01001000 01101001	10010110 00010010	00010010 10010110	01101001 01001000
Hex (32-bit)	DE AD BE EF	11011110 10101101 10111110 11101111	11110111 01111101 10110101 01111011	01111011 10110101 01111101 11110111	11101111 10111110 10101101 11011110
Binary	1	00000001	10000000	10000000	00000001
Binary	11111111	11111111	11111111	11111111	11111111
Decimal	0	00000000	00000000	00000000	00000000
Decimal	255	11111111	11111111	11111111	11111111
Hex	FF	11111111	11111111	11111111	11111111
ASCII	Z	01011010	01011010	01011010	01011010

Frequently Asked Questions

Full-stream reversal treats the entire binary input as a single sequence and mirrors it end-to-end. Per-byte reversal pads the input to a multiple of 8 bits, splits it into 8-bit groups, and reverses each byte independently while keeping byte order intact. For a single byte, both produce the same result. For multi-byte data, results differ significantly. For example, 10110010 01001101 full-reversed becomes 1011001001001101, while per-byte reversed becomes 01001101 10110010.

Byte-order reversal (endianness swap) is used when converting data between big-endian and little-endian architectures. Network protocols typically use big-endian (network byte order), while x86 processors use little-endian. This mode rearranges whole bytes without touching the bit ordering within each byte. Use this when debugging protocol buffers, file format headers (e.g., TIFF, BMP), or cross-platform serialized data.

For per-byte and byte-order modes, the tool zero-pads the binary string on the left until its length is a multiple of 8. For example, input 101 (3 bits) becomes 00000101 (8 bits) before processing. Full-stream mode can operate on any length without padding, though a padding option is available. The padding is always shown in the output so you can verify the assumed bit width.

Yes. Enter the hex bytes from your file header (e.g., DE AD BE EF), select byte-order reversal mode, and the tool will output EF BE AD DE in hex. This is the exact operation performed by functions like htonl() and ntohl() in C networking libraries. Compare the reversed output against the format specification to verify correctness.

The tool accepts up to 10,000 characters of input in any format. Binary reversal is an O(n) string operation and completes in under 1 millisecond for typical inputs. For the maximum length (10,000 binary digits = 1,250 bytes), processing remains instantaneous. The bottleneck, if any, is DOM rendering of the formatted output, not the algorithm itself.

Not necessarily. Bit reversal preserves the number of 1-bits (Hamming weight), so the popcount remains identical. However, the numerical value changes unpredictably. The reversed value of an even number can be odd and vice versa, because parity depends on the least significant bit, which after reversal was formerly the most significant bit. The only values invariant under full reversal within a fixed bit width are binary palindromes (e.g., 10000001, 01011010).