ASCII Decoder converts a list of decimal ASCII codes back into readable text. Paste space-separated numbers like "72 101 108 108 111" and get the original string ("Hello"). Use it to decode byte arrays from hardware serial output, interpret ASCII-encoded data in log files, or solve character encoding problems in CTF challenges.
The decoder splits the input on whitespace to get individual number strings, parses each as a decimal integer, and converts it to a character using JavaScript's String.fromCharCode(). The resulting characters are joined to produce the decoded string. Numbers 0–127 map to standard ASCII characters. Numbers 128–255 map to extended ASCII or Latin-1 characters.
Yes, the decoder splits on whitespace to identify individual code values. Without separators, "7210" is ambiguous — it could be codes 72 and 10, or 7, 2, 1, 0. Space-separated input removes this ambiguity.
Standard ASCII covers 0–127. Numbers 128–255 map to extended ASCII or Latin-1 characters (like accented letters and symbols). Numbers above 255 are not valid single-byte ASCII codes and may produce unexpected results.
No, this tool expects decimal (base-10) numbers. If your data is in hexadecimal like "48 65 6C 6C 6F", use the Hex to Text tool instead.
Codes 0–31 and 127 are control characters (tab=9, newline=10, carriage return=13, null=0). They may not produce visible glyphs in the output but are valid ASCII codes. A space (code 32) produces a visible space character.
No. Decoding runs entirely in your browser. Your data never leaves your device.
Tool workspace
Free ASCII Decoder online — instantly translate spaced ASCII decimal values back into human-readable strings. Perfect for hardware debugging, reverse engineering, and CTF challenges. No login.
Output
Input
87 111 114 108 100
Output
World
