ASCII Table — 0–127, Extended 128–255 and Alt Codes

Printable ASCII characters (32–126)

The characters you actually type: space, digits, uppercase and lowercase letters, and punctuation. Every keyboard on Earth speaks these.

ASCII control characters (0–31 and 127)

These are the non-printable codes. Most were designed for teletypes and are now obsolete, but a handful drive modern text (line feed, carriage return, tab, null) and terminal control (escape).

Convert between characters and codes in code

Excel and Google Sheets — CODE returns the number for a character, CHAR returns the character for a number:
=CODE("A")     → 65
=CHAR(65)      → A
=CHAR(9)       → tab character
=CHAR(10)      → line feed (use in a wrapped cell for a manual line break)

Python — ord and chr do the same:
ord("A")       # 65
chr(65)        # "A"
chr(10)        # "\n"

JavaScript — charCodeAt and String.fromCharCode:
"A".charCodeAt(0)          // 65
String.fromCharCode(65)    // "A"

What comes after 127 — extended ASCII and UTF-8

ASCII ends at 127. The bytes from 128 to 255 are NOT standard ASCII — they belong to whichever 8-bit codepage the file was saved in (Latin-1 / ISO-8859-1 in Western Europe, Windows-1252, various regional codepages). "Extended ASCII" is really a marketing term for that legacy byte range, and different codepages assign different characters to the same byte, which is the classic cause of "mojibake" (garbled characters) when a file is opened in the wrong encoding.

UTF-8 solved this by encoding every Unicode character (over 150,000 of them and counting) as one to four bytes, with the property that any pure-ASCII text is bit-for-bit identical in UTF-8. That is why saving a plain English text file as ASCII or as UTF-8 produces the same file. The binary-hex reference on this site covers the byte-level view, and the HTML entities tool converts between characters and their HTML entity names for the ones you cannot type directly.

Extended ASCII table (128–255) — Windows-1252

This is the table most people mean by “extended ASCII”: the Windows-1252 code page, the default on Western-language Windows and the encoding Excel still uses when you save a plain “CSV (Comma delimited)” file. Codes 160–255 are identical in ISO-8859-1 (Latin-1) and match Unicode U+00A0–U+00FF one-to-one. Codes 128–159 are where the two disagree: Windows-1252 puts €, the curly quotes, the dashes and ™ there, while Latin-1 leaves them as invisible control codes. Five codes (129, 141, 143, 144 and 157) are unassigned. The last column is the Windows keystroke that types each character — see the next section.

Alt codes for symbols and accented letters (Windows and Mac)

Windows has two Alt-code systems, which is why the same character shows up online with two different numbers. Alt plus a number WITHOUT a leading zero uses the old DOS code page (437 on US Windows, 850 on most European and Latin American Windows); Alt plus 0 plus a number uses Windows-1252 — the table above. The Alt+0 codes are the same on every Western-language Windows, so they are the safer ones to memorize.

1. Turn on Num Lock.
2. Hold down the left Alt key.
3. Type the number on the numeric keypad — the digit row above the letters does not work.
4. Release Alt and the character appears.
5. No numeric keypad (most laptops)? Press Win + . (period) for the emoji and symbol panel, or open Character Map (charmap). On a Mac, use the Option shortcuts in the table.

The Spanish letters follow a pattern worth knowing: in the DOS codes the lowercase accented vowels sit together at Alt+160 (á), 161 (í), 162 (ó) and 163 (ú), with é off on its own at 130; ñ is 164 and Ñ is 165. If the character has to go into HTML rather than a document, the HTML entities reference lists the named entities (ñ, é) instead.

What about a check mark (✓)? It is not ASCII and not in Windows-1252, so there is no true Alt code for it. What works: on Windows, Win + . (period) opens the symbol panel, which has ✓; in Excel, =UNICHAR(10003) gives ✓ and =UNICHAR(10004) the heavy ✔; in Word, type ü (Alt+0252) and switch the font to Wingdings. The Alt+251 trick you will see online gives √ (a square-root sign often used as a check) on English Windows, but ¹ on Spanish-language Windows. On a Mac, Option+V types √.

Why you see ñ instead of ñ (mojibake)

When UTF-8 text is opened as Windows-1252, every non-ASCII character turns into two or three wrong ones. UTF-8 stores ñ as two bytes, C3 B1; Windows-1252 reads each byte on its own — C3 is Ã, B1 is ± — so “España” becomes “España”. It is the classic result of opening a CSV exported from a website, an app or a database by double-clicking it in Excel. The damage is so regular you can read it backwards:

The opposite mistake looks different. A file saved as Windows-1252 or Latin-1 stores ñ as the single byte F1, which is not valid UTF-8 on its own, so a UTF-8 reader shows the replacement character instead: “Espa�a”. Rule of thumb: à and  pairs mean UTF-8 read as 1252; lone � diamonds mean 1252 read as UTF-8.

Excel — open a UTF-8 CSV correctly:
  Data → From Text/CSV → File origin: 65001 : Unicode (UTF-8)
Excel — save so other tools read it correctly:
  File → Save As → "CSV UTF-8 (Comma delimited)"

Python — repair text that is already mangled (UTF-8 read as 1252):
"España".encode("cp1252").decode("utf-8")   # "España"
# messier cases: pip install ftfy, then ftfy.fix_text(s)

Python — read a legacy Windows file without the � marks:
open("data.csv", encoding="cp1252").read()

HTML — declare the encoding at the top of <head>:
<meta charset="utf-8">