ASCII Table

The ASCII Table is an interactive reference for all 128 characters in the 7-bit American Standard Code for Information Interchange. Every row shows the decimal, hexadecimal, octal, and binary value of a character, along with its name. It is designed for the moments when you need to know that a space is 32, that A is 65, or which code is quietly breaking your parser, without opening a language runtime to check.

How to Use

The full table of 128 rows is scrollable, and category filters narrow it to control characters, digits, uppercase letters, lowercase letters, or punctuation. The search box accepts a value in any of the displayed bases, a control-character name such as ESC, or a literal character such as A.

• Type 65 to jump to the capital A.
• Type 41 to find the same character by hex.
• Type NL or LF to find the line feed.
• Pick the control filter to see only codes 0-31 and 127.

Results keep the table’s original order, so a search is a highlight rather than a re-sort.

Reading a Row

Each row has six columns. Take the capital letter A:

Field	Value
Character	A
Decimal	65
Hex	41
Octal	101
Binary	1000001
Category	uppercase

Three more useful rows:

Char	Dec	Hex	Oct	Binary
(space)	32	20	040	0100000
a	97	61	141	1100001
LF	10	0A	012	0001010

The relationship between the cases is worth memorising: lowercase letters are exactly 32 above their uppercase counterparts, so a (97) minus A (65) is 32, and converting case is a matter of adding or subtracting that offset.

The Four Ranges of the Table

The 128 codes are not uniform. The categories the tool uses are:

• Control, 0-31 and 127 — historically drove teletypes and printers; today used for line endings, tabs, and escape sequences.
• Punctuation and symbols, 32-47, 58-64, 91-96, 123-126 — the space plus everything that is not a letter or digit.
• Digits, 48-57 — 0 through 9 in order, so '7' - '0' gives the integer 7 in C-like languages.
• Uppercase 65-90, lowercase 97-122 — two contiguous alphabetic blocks.

The grouping is a historical design choice rather than a strict rule, which is why the punctuation codes are scattered in gaps between the letter and digit blocks.

Control Characters You Still Use

Most of the control block is obsolete, but a handful appear in real files and configs every day:

Code	Hex	Name	Modern use
0	00	NULL	String terminators in C, padding
7	07	BEL	Terminal bell
8	08	BS	Backspace
9	09	TAB	Indentation, TSV files
10	0A	LF	Unix/macOS line ending
12	0C	FF	Form feed, page breaks
13	0D	CR	Part of Windows CRLF
27	1B	ESC	ANSI escape sequences
127	7F	DEL	Delete

If you have ever opened a CSV and seen ^M at the end of each line, that is a CR (13) left over from a Windows-produced file.

How ASCII Fits Inside UTF-8

The reason this table stops at 127 is that everything above it belongs to a different encoding. UTF-8 was designed so that its first 128 code points are byte-for-byte identical to ASCII: U+0041 A is the single byte 0x41, exactly as shown here. Above that range, UTF-8 uses two, three, or four bytes per character, and the first byte always has its high bit set.

A concrete example: the character é is U+00E9, which UTF-8 stores as the two bytes 0xC3 0xA9. Neither byte is an ASCII code, even though the sequence renders as one letter. That distinction matters when you are scanning a file for control bytes. In valid UTF-8, every byte from 0x00 to 0x7F is exactly the ASCII character listed in this table, while any byte of 0x80 or higher is part of a multi-byte sequence or an invalid byte.

Older single-byte encodings such as ISO-8859-1 (Latin-1) do map bytes 128-255 directly to accented characters, which is why a file can look correct in one editor and garbled in another. This table deliberately covers only the 7-bit range, so a value of 130 or higher tells you the data is not plain ASCII.

Common Mistakes

• Confusing a byte with a code point. An ASCII code is a number from 0 to 127. The fact that it is often padded into an 8-bit byte does not mean bit 8 is part of ASCII.
• Assuming octal has no leading zero. The printf escape \101 means octal 101 = decimal 65 = A. The table pads octal values to three digits for exactly this reason.
• Mixing up CR and LF when generating line endings. Writing only CR, or LF where CRLF is expected, can break Windows tools and produce text that all appears on one line.
• Treating code-page characters as ASCII. Bytes 128-255 (accented letters, smart quotes) are not ASCII; they belong to extensions such as Latin-1 or Windows-1252 and require a different lookup.

Use Cases

• Debugging text where an invisible control character is breaking a parser or a diff.
• Learning how character codes relate to their integer values, and why 'A' is 65.
• Writing shell printf or echo -e escape sequences and needing the octal or hex form.
• Checking the exact byte that separates columns in TSV (TAB, 9) versus CSV (comma, 44).
• Verifying that a file is plain ASCII before shipping it to a system that cannot handle Unicode.

Related Tools

• Unicode Finder
• Text to Binary
• Number Base Converter