About

ASCII (American Standard Code for Information Interchange) maps 128 characters to integer values in the range 0 - 127. Extended ASCII expands this to 256 code points (0 - 255), covering Latin-supplement glyphs. Misinterpreting a single code - confusing 65 (A) with 97 (a) - corrupts data streams, breaks serial protocols, and produces garbled output in embedded firmware logs. This converter performs bidirectional translation between decimal ASCII codes and their character representations, handling any delimiter format automatically.

The tool validates every code against the 0 - 255 boundary and flags out-of-range values rather than silently dropping them. Limitation: this operates on single-byte encodings only. Multi-byte sequences (UTF-8 codepoints above 255) require a Unicode converter. Pro tip: when pasting codes from serial monitor output, select the matching delimiter or use auto-detect to avoid manual reformatting.

Formulas

ASCII-to-Text conversion applies the character mapping function for each decimal code c in the input sequence:

char(c) = fromCharCode(c), 0 ≤ c ≤ 255

The reverse operation extracts the ordinal value of each character ch in a string S:

code(ch) = charCodeAt(ch), ch ∈ S

The full output string T is the concatenation across all n input tokens:

T = n∑i=1 char(c_i)

Where c = decimal ASCII code (0 - 255), ch = single character from input string, S = input string, n = total number of tokens or characters, and T = resulting converted text.

Reference Data

Dec	Hex	Char	Description
0	00	NUL	Null
7	07	BEL	Bell / Alert
8	08	BS	Backspace
9	09	HT	Horizontal Tab
10	0A	LF	Line Feed (newline)
13	0D	CR	Carriage Return
27	1B	ESC	Escape
32	20	SP	Space
48 - 57	30 - 39	0 - 9	Digits
65 - 90	41 - 5A	A - Z	Uppercase Latin
97 - 122	61 - 7A	a - z	Lowercase Latin
33	21	!	Exclamation Mark
34	22	"	Quotation Mark
35	23	#	Number Sign
40	28	(	Left Parenthesis
41	29	)	Right Parenthesis
43	2B	+	Plus Sign
45	2D	-	Hyphen-Minus
46	2E	.	Full Stop / Period
64	40	@	At Sign
91	5B	[	Left Square Bracket
92	5C	\	Backslash
93	5D	]	Right Square Bracket
123	7B	{	Left Curly Bracket
125	7D	}	Right Curly Bracket
126	7E	~	Tilde
127	7F	DEL	Delete
128	80	€	Euro Sign (Win-1252)
169	A9	©	Copyright Sign
176	B0	°	Degree Sign
181	B5	μ	Micro Sign
255	FF	ÿ	Latin Small y with Diaeresis

Frequently Asked Questions

Codes above 255 fall outside the single-byte extended ASCII range. The converter flags these as out-of-range errors and marks them with a ⚠ symbol in the output rather than silently producing incorrect characters. For codepoints above 255, you need a Unicode/UTF-8 converter that handles multi-byte sequences.

The converter tests the input string against four patterns in priority order: comma-separated (e.g., 72,101,108), space-separated, tab-separated, and newline-separated. It counts the occurrences of each candidate delimiter and selects the one that produces the most valid numeric tokens. If no delimiter yields valid results, it falls back to treating the entire input as a single number.

Characters in the range 0 - 31 are non-printable control codes. Rendering them directly produces invisible or disruptive output (e.g., code 7 triggers a system bell). The converter substitutes their standard abbreviations (NUL, SOH, STX, BEL, BS, HT, LF, CR, ESC, etc.) wrapped in brackets so you can identify them without side effects.

This tool processes decimal ASCII codes. If you have hexadecimal values (e.g., 48, 65, 6C), enable the Hex input mode toggle. The converter will parse each token as base-16 and convert to the corresponding character. Binary input is not directly supported; convert binary to decimal first.

Standard ASCII defines 128 characters (codes 0 - 127), covering English letters, digits, punctuation, and control codes. Extended ASCII adds another 128 characters (codes 128 - 255), but these vary by code page. Windows-1252, ISO-8859-1, and IBM Code Page 437 all define different characters for the same codes above 127. This converter uses the browser's native fromCharCode mapping, which aligns with Unicode's first 256 codepoints (identical to ISO-8859-1).

Yes. When converting Text to ASCII, each newline character is encoded as its decimal code: 10 for LF (Unix/Mac) or the pair 13, 10 for CR+LF (Windows). The output preserves the exact byte sequence of your input. When converting back, those codes reproduce the original line breaks.