What the ASCII Converter does
This converter turns text into ASCII codes - in decimal, hexadecimal, binary or octal - and turns a list of codes back into text. Type "Hi!" and you get 72 105 33 (hex 48 69 21); paste 01001000 01101001 and you get "Hi". A full 0-127 ASCII table sits underneath for reference.
It is also honest about what is not ASCII. ASCII has only 128 codes, so letters such as é, ñ or ü, currency signs like € and every emoji fall outside it. Those characters are flagged, and you choose whether to show their Unicode code point (é = 233) or the UTF-8 bytes a file or web page actually stores (é = C3 A9). Everything runs in your browser.
How to use it
- Choose Text to ASCII codes to encode, or Codes to text to decode. Swap direction moves the result into the input and flips the mode.
- Type or paste. For decoding, codes can be separated by spaces, commas or new lines, carry prefixes such as 0x, \x, 0b or U+, be HTML references like H, or be one unbroken run of binary or hex bytes.
- Pick the number base. When decoding, the page guesses the base from what you paste until you choose one yourself.
- Decide how characters above 127 are handled: as Unicode code points, or as UTF-8 bytes. Under Output format you can change the separator and add 0x or \x prefixes for code.
- Copy the result, download it as text, or download a CSV with every character's decimal, hex, binary, octal, Unicode and UTF-8 values.
Reading the results
The headline says how many characters you entered and whether they are all plain 7-bit ASCII. If they are, the text is byte-for-byte identical in ASCII, UTF-8 and Latin-1, which is why ASCII-only text never turns into garbled symbols when it moves between systems.
A warning lists every character outside ASCII with its code point and its UTF-8 bytes. One character can be two, three or four bytes in UTF-8, so the byte count can be larger than the character count.
Control characters (codes 0-31 and 127) are invisible but real: a line break is LF (10), or CR LF (13 10) on Windows; a tab is HT (9). The table names them so you can see exactly what is hidden in pasted text.
When decoding, any token that is not a valid number in the chosen base, is above the Unicode maximum or is not a byte in UTF-8 mode is listed by itself; everything else is still decoded.
Worked example: encoding "Café" for a file and for a program
C, a and f are ASCII: 67, 97 and 102 in decimal, 43, 61 and 66 in hex. In binary they are 01000011 01100001 01100110.
é is not ASCII. Its Unicode code point is U+00E9, which is 233 in decimal. In UTF-8 - the encoding almost every web page and modern file uses - it is stored as two bytes, C3 A9 (195 169).
So "Café" is 4 characters but 5 bytes in UTF-8: 43 61 66 C3 A9. If those bytes are read as Latin-1 by mistake, C3 and A9 display as à and ©, producing the familiar "Café" error. Decoding 43 61 66 C3 A9 here in UTF-8 mode gives back "Café"; decoding it as code points shows exactly that mistake.
What ASCII is, and what it is not
ASCII, the American Standard Code for Information Interchange, was published in 1963 and fixed as ANSI X3.4-1968; RFC 20 adopted it for network interchange in 1969. It uses 7 bits, so it has exactly 128 codes: 33 control codes (0-31 and 127, such as tab, line feed and escape) and 95 printable characters (32-126: space, digits, the English alphabet in both cases and common punctuation).
"Extended ASCII" is not one standard. Codes 128-255 meant different things in different code pages - Latin-1, Windows-1252, IBM 437 - which is why this page never assigns an "ASCII code" above 127. Unicode replaced that confusion: it gives every character one code point, and its first 128 code points are ASCII, unchanged.
Code points versus UTF-8 bytes
A code point is the character's number in Unicode, written U+00E9. UTF-8 is how that number is stored: ASCII characters stay as one byte, accented Latin letters take two, most other scripts three, and emoji four. Choose code points when you need a character's identity (for an HTML reference such as é) and UTF-8 bytes when you are reading a hex dump, a URL escape or a network capture.
Limitations: what the result does not prove
- Codes above 127 are only meaningful with a stated encoding. This page offers Unicode code points and UTF-8; it does not decode legacy code pages such as Windows-1252 or Shift-JIS.
- A character you see can be several code points - a letter plus a combining accent, or an emoji with a skin-tone modifier - and each code point is listed separately.
- It converts characters to numbers and back; it does not encrypt or compress anything, and binary here is just a way of writing the same numbers.
- Input is limited to 20,000 characters or 50,000 codes per conversion.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- RFC 20 - ASCII format for network interchange - checked 19 Sep 2026
- RFC 3629 - UTF-8, a transformation format of ISO 10646
- Unicode code chart - C0 Controls and Basic Latin (U+0000-U+007F)
- The Unicode Standard - Chapter 2, general structure and encoding forms
Frequently asked questions
What is the ASCII code for the letter A?
Capital A is 65 in decimal, 41 in hexadecimal, 101 in octal and 1000001 in binary. Small a is 97 (hex 61). Every capital letter is exactly 32 below its small letter, which is why the two differ by a single bit.
How do I convert text to binary ASCII?
Choose Text to ASCII codes, set the base to Binary and type your text. Each character becomes an 8-bit group: Hi is 01001000 01101001. Copy the result or download it; characters outside ASCII are shown as code points or UTF-8 bytes, as you choose.
How do I decode a string of ASCII numbers back to text?
Switch to Codes to text and paste the numbers, separated by spaces or commas. The page guesses whether they are decimal, hex or binary and decodes them as you type. A value it cannot read is listed by itself and the rest still decode.
Does é or € have an ASCII code?
No. ASCII stops at 127 and contains only unaccented English letters, digits and basic punctuation. é is Unicode U+00E9 (233) and € is U+20AC (8364); in UTF-8 they are stored as C3 A9 and E2 82 AC. This page flags such characters instead of inventing an ASCII code.
What is the difference between ASCII and Unicode?
ASCII is a 7-bit code with 128 characters for English. Unicode numbers over 150,000 characters from every writing system plus symbols and emoji, and its first 128 code points are exactly ASCII. UTF-8 then stores Unicode so that plain ASCII text stays one byte per character.
What are ASCII control characters such as LF, CR and NUL?
They are the codes 0-31 and 127, originally commands for teleprinters rather than printable symbols. The ones you still meet are tab (9), line feed (10), carriage return (13) and escape (27); NUL (0) marks the end of a string in C. The table names all 33.
Why does text show strange characters like é instead of é?
The UTF-8 bytes C3 A9 for é were read as a single-byte encoding, where C3 is à and A9 is ©. Decode the bytes here in UTF-8 bytes mode to get é back; decode them as code points to reproduce the error and confirm the cause.
Last reviewed by the A2Z.Tools team against the sources listed above.
