Is &#xHHHH; a real, standard HTML notation?

Yes. Hexadecimal numeric character references, written as &#x followed by the code point in hex and a semicolon, are part of the HTML Living Standard and XML specifications, not an invented format. Browsers and XML parsers are required to understand them, and they can represent any Unicode code point, not just a small fixed set of named entities.

How is this different from the named HTML entity encoder elsewhere on this site?

The named HTML entity encoder (in the string tools category) escapes exactly five HTML-significant characters (&, , ", ') into their named entities like & and <, for XSS-safety when embedding untrusted text into markup. This tool instead encodes every character of the input, using its numeric code point in hexadecimal, which is useful any time you need a code-point-explicit representation of arbitrary Unicode text rather than markup-safety escaping specifically.

Does this handle emoji and other characters outside the Basic Multilingual Plane correctly?

Yes. The tool iterates the input using JavaScript's code-point-aware iteration (the spread operator over a string), which correctly groups UTF-16 surrogate pairs into a single character before encoding, rather than iterating by raw UTF-16 code unit. That means an emoji like \u{1F600} produces one correct reference, 😀, instead of two broken half-references.

Is my text sent to a server?

No. The encoding runs entirely in your browser using JavaScript's built-in codePointAt, so nothing you type here is transmitted anywhere.

Characters to Hex HTML Entities Converter

Q: Does this handle emoji and other characters outside the Basic Multilingual Plane correctly?

Yes. The tool iterates the input using JavaScript's code-point-aware iteration (the spread operator over a string), which correctly groups UTF-16 surrogate pairs into a single character before encoding, rather than iterating by raw UTF-16 code unit. That means an emoji like \u{1F600} produces one correct reference, 😀, instead of two broken half-references.

Q: Is my text sent to a server?

No. The encoding runs entirely in your browser using JavaScript's built-in codePointAt, so nothing you type here is transmitted anywhere.

Overview

Introduction

Hexadecimal HTML/XML character references are a real, standard way to represent any Unicode character in markup using its code point in hex, written as &#xHHHH;.

This tool encodes every character of your input this way, correctly handling characters outside the Basic Multilingual Plane (like most emoji) by iterating per Unicode code point rather than per UTF-16 code unit.

What Is Characters to Hex HTML Entities Converter?

A hexadecimal character reference is the sequence &#x, followed by a Unicode code point written in hexadecimal, followed by a semicolon. "é" (code point U+00E9) becomes é.

Both HTML and XML parsers recognize this notation for any valid Unicode code point, unlike the small, fixed set of named entities (like & or ©), which only cover specific characters.

How Characters to Hex HTML Entities Converter Works

The tool spreads the input string into an array of Unicode code points (not raw UTF-16 code units), so multi-code-unit characters like emoji are treated as a single character rather than two broken halves.

Each code point is converted to hexadecimal via toString(16), uppercased, and wrapped in the &#x...; reference syntax, then all references are concatenated in the original order.

When To Use Characters to Hex HTML Entities Converter

Use this when you need every character of some text represented explicitly by its Unicode code point, for instance while debugging character-encoding issues, building test fixtures, or embedding text in a system that only reliably supports ASCII markup.

For markup-safety escaping (protecting against XSS when inserting untrusted text into HTML), use this site's HTML Entity Encoder tool instead, which escapes only the five HTML-significant characters rather than every character.

Often used alongside Hex HTML Entities to Characters Converter.

Features

Advantages

Uses a real, standard notation understood by every HTML and XML parser, not an invented format.
Correctly handles the full Unicode range, including characters outside the Basic Multilingual Plane like most emoji.
Fully reversible with the companion hex-html-entities-to-characters-converter tool.

Limitations

Encodes every character, not just markup-significant ones, so output is far more verbose than the five-character HTML Entity Encoder tool for typical markup-safety use cases.
Numeric character references don't carry any semantic meaning the way some named entities do (e.g. © documents intent as well as encoding the symbol).
Doesn't validate that the input is meant for HTML/XML at all; it will happily encode any text you give it.

Examples

Encoding an accented character

Input

é

Output

&#xE9;

U+00E9 (é) in hexadecimal is E9, wrapped in the standard &#x...; reference syntax.

Encoding an emoji outside the Basic Multilingual Plane

Input

😀

Output

&#x1F600;

This emoji's code point, U+1F600, is above the Basic Multilingual Plane and spans two UTF-16 code units; code-point-aware iteration still encodes it as a single correct reference.

Best Practices & Notes

Best Practices

Use this for code-point-explicit representations of arbitrary text, not as a substitute for markup-safety escaping (use the HTML Entity Encoder tool for that).
Pair with hex-html-entities-to-characters-converter to confirm a lossless round trip on your own text, including any emoji.
Remember output is verbose (roughly 6-9 characters per input character), so this isn't a compact encoding.

Developer Notes

Implemented with the spread operator over the input string (`[...input]`), which iterates by Unicode code point per the ECMAScript string iterator protocol, then `codePointAt(0)!.toString(16).toUpperCase()` per character. This correctly handles astral characters (surrogate pairs) as a single unit, unlike a naive `for (let i = 0; i < input.length; i++)` loop over UTF-16 code units, which would split them incorrectly.