Unicode Converter — Code Points and UTF-8 Bytes

What it is

Type some text and you get every common notation at once, each with a copy button: Unicode code points, JavaScript and JSON escapes, the ES6 form, HTML hex and decimal references, and the raw UTF-8 and UTF-16BE bytes. Use it to put non-ASCII text into source code safely, read the \uXXXX sequences in a log, or find out why text turned into mojibake.

It also compares byte counts in UTF-8, UTF-16 and the legacy Korean encoding EUC-KR (CP949), and lists each code point in a table. The reverse direction turns escapes or hex bytes back into text. Everything runs in your browser and nothing is stored.

How to use

1. Pick a direction: Text → code or Code → text.
2. For Text → code, type in the text box. The example “Café 😀 한” is already there, so results appear right away.
3. Turn off “Keep ASCII as is” to escape every character, not just the non-ASCII ones.
4. Copy the format you need. The byte comparison and the character table are below.
5. For Code → text, keep Auto-detect for escapes and U+ values, even mixed together, or pick a hex byte format for byte lists.
6. Copy the decoded text with its button.

How it works

• Code points are written as U+ followed by uppercase hex, padded to at least four digits (U+0041), separated by spaces.
• JavaScript / JSON escapes write one \uXXXX per UTF-16 code unit, so anything from U+10000 up becomes a surrogate pair. The ES6 form writes one \u{...} per code point.
• HTML references write one &#x…; or &#…; per code point.
• Keep ASCII as is leaves printable ASCII (U+0020 to U+007E) unchanged, except the backslash (JavaScript) and & < > “ ’ (HTML), so the output decodes back unambiguously. Line breaks and tabs are always escaped.
• UTF-8 bytes come from the browser’s TextEncoder. UTF-16 writes two bytes per code unit, most significant byte first (big-endian).
• EUC-KR (CP949): a reverse lookup is built by decoding every two-byte pair (lead 0x81 to 0xFE, trail 0x41 to 0xFE) with the browser’s EUC-KR decoder; ASCII is one byte. All 11,172 syllables from 가 to 힣 take two bytes: 2,350 from KS X 1001 and 8,822 from the CP949 (UHC) extension, which is filled in by CP949’s layout if a decoder only knows KS X 1001.
• Visible characters are grapheme clusters from the browser’s Intl.Segmenter (Unicode Standard Annex #29). The table has one row per code point, marks multi-code-point characters and shows the first 200.
• Decoding: U+ values take 4 to 8 hex digits, and spaces or commas between U+ values are treated as separators. Values above U+10FFFF and unpaired surrogates are reported with the character position. Byte input ignores spaces, commas, colons, hyphens and 0x, \x or % prefixes, and invalid UTF-8 is reported with the byte position.
• Input is limited to 20,000 characters.

Examples

Text	Code point	JavaScript	UTF-8 bytes	UTF-8 / UTF-16 / EUC-KR
A	U+0041	A (or \u0041 with Keep ASCII off)	41	1 / 2 / 1 bytes
é	U+00E9	\u00E9	C3 A9	2 / 2 / not encodable
中	U+4E2D	\u4E2D	E4 B8 AD	3 / 2 / 2 bytes
한	U+D55C	\uD55C	ED 95 9C	3 / 2 / 2 bytes
😀	U+1F600	\uD83D\uDE00	F0 9F 98 80	4 / 4 / not encodable

The default example “Café 😀 한” has 8 visible characters, 8 code points and a UTF-16 length of 9. It takes 14 bytes in UTF-8, 18 in UTF-16 and 7 in EUC-KR, where é and the emoji cannot be represented.

Going the other way, auto-detect turns Caf\u00E9 😀 U+D55C into “Café 😀 한”, and the UTF-8 bytes 43 61 66 C3 A9 decode to “Café”.