Unicode Escape Converter: Encode and Decode Unicode Sequences

How to use the unicode escape converter

1. Paste your text into the Input text field, or paste an already-escaped string if you want to decode it.
2. Select Encode to convert plain text to a unicode escape sequence, or Decode to reverse the process.
3. Choose your target format: JavaScript \uXXXX, ES6 \u{...}, U+ notation, or HTML hex entities.
4. Check Escape ASCII characters too if you need every character encoded, not just non-ASCII ones.
5. Copy the result from the output box. The conversion happens instantly in your browser.

How unicode escape sequences work

A unicode escape sequence represents a character by its numeric code point rather than its visual glyph. In JavaScript, the classic form is \uXXXX where XXXX is exactly four hexadecimal digits. For example, the letter e with an acute accent (é) has code point U+00E9, so its escape is \u00e9.

This works perfectly for the Basic Multilingual Plane (BMP), which covers code points U+0000 through U+FFFF. Characters beyond that range, such as most emoji, require either two \uXXXX sequences called a surrogate pair, or the newer ES6 syntax \u{XXXXX} which accepts one to six hex digits directly.

Surrogate pairs explained

UTF-16 encodes characters above U+FFFF using two 16-bit code units: a high surrogate (range D800 to DBFF) and a low surrogate (range DC00 to DFFF). To escape unicode characters like the globe emoji (U+1F30D) in the classic \uXXXX format, the converter performs this math:

1. Subtract 0x10000 from the code point: 0x1F30D - 0x10000 = 0xF30D.
2. The high ten bits become the high surrogate: 0xD800 + (0xF30D >> 10) = 0xD83C.
3. The low ten bits become the low surrogate: 0xDC00 + (0xF30D & 0x3FF) = 0xDF0D.

The result is \ud83c\udf0d. Python's json.dumps() produces the same paired output when ensure_ascii=True. When decoding, this tool detects valid surrogate pairs and merges them back into a single character.

Format comparison table

Different languages and contexts expect different ways to write a unicode escape. Here is how the character é (U+00E9) and the globe emoji (U+1F30D) look across the four supported formats:

The U+ notation is typically used in documentation and character maps rather than source code. HTML hex entities are parsed by browsers but not by JavaScript engines directly.

Practical use cases

Developers frequently need to escape unicode when preparing strings for JSON payloads, configuration files, or legacy systems that only accept ASCII input. If you are working with broader string escaping needs, the string escape tool handles quotes, newlines, and tabs alongside unicode. For web-specific markup, the HTML escape tool converts angle brackets and ampersands safely.

Another common scenario is debugging garbled text. If a database returns \u00e9 instead of é, pasting that string into this converter in decode mode reveals the original text immediately. You can also verify that your output matches what Python would produce: running 'café'.encode('ascii', 'backslashreplace') yields b'caf\\xe9', while json.dumps('café') gives "caf\u00e9", matching the JavaScript format here.

Common mistakes when converting

One frequent error is confusing UTF-8 byte escapes with unicode code point escapes. The character é is two bytes in UTF-8 (0xC3 0xA9), but its code point is 0x00E9. A unicode escape always refers to the code point, never the raw bytes. If you need byte-level conversions, look at tools like text to binary or base64 encoding instead.

Another pitfall is broken surrogate pairs. If a string contains a high surrogate without a following low surrogate, it is technically invalid UTF-16. This converter treats isolated surrogates as individual code units when encoding, and leaves them unmerged when decoding, preventing data loss even on malformed input.

Worked examples