Binary Decoder converts binary strings back into readable text. Paste space-separated 8-bit binary groups (like "01001000 01101001") and get the decoded text ("Hi"). Use it to decode CTF challenges, read binary-encoded messages, or verify binary encoding exercises in computer science courses.
The decoder splits the input on spaces to get 8-bit groups. Each group is parsed as a base-2 binary number using parseInt(bits, 2) to get a decimal value. That decimal is then converted to a character using String.fromCharCode(). For example, 01000001 → decimal 65 → "A". Without spaces, the decoder groups bits in 8s from left to right.
Spaces are recommended but not required. Without spaces, the decoder groups bits into 8s from left to right. So "0100100001101001" is treated as "01001000 01101001" and decodes to "Hi". If the total number of bits is not divisible by 8, the decoder may not produce the expected result.
The decoder only understands 0 and 1. If the input contains letters, spaces within a byte group, or other characters, the decode operation will fail or produce unexpected output. Make sure the binary input contains only 0s, 1s, and spaces between bytes.
No. Binary encoding and decoding is a reversible transformation that any tool can perform without a key. It represents text using a different notation (base 2) but does not hide the data. Real encryption requires a secret key and cannot be reversed without it.
If each byte of a UTF-8 multi-byte sequence is included in the binary input, the decoder converts the bytes back and JavaScript interprets the resulting byte values. However, the tool works best with standard ASCII characters (one byte each).
No. Decoding runs entirely in your browser. Your binary data never leaves your device.
Tool workspace
Free Binary Decoder online — instantly translate strings of binary (0s and 1s) directly back to readable text format. Handles 8-bit octet arrays. No login.
Output
Input
01101000 01101001
Output
hi
