HTML entities are special codes used to represent characters in HTML documents. They allow you to display characters that might otherwise be interpreted as HTML markup (like < and >) or characters that aren't easily typed on a keyboard. Unicode HTML entities cover the full range of Unicode characters — over 143,000 characters spanning all major writing systems, symbols, and emoji.

Decimal entities use the format A (base-10 Unicode code point).
Hexadecimal entities use A (base-16, prefixed with x).
Named entities use mnemonic names like & or €. Named entities are easier to read but only exist for about 2,000 characters (mostly Latin-1, Greek, math symbols, and arrows). For all other characters, numeric entities must be used. All three formats are equally valid in HTML5.

Use Special Chars Only when embedding user-generated content in HTML to prevent rendering issues and XSS — it converts only <, >, &, ", and '. Use Non-ASCII Only for international text where ASCII characters should remain readable but accented or Unicode characters need safe encoding. Use All Characters for complete obfuscation, email address protection from bots, or when you want every single character represented as an entity.

Yes, encoding special HTML characters (< → <, > → >, & → &, " → ", ' → ') is a critical defense against Cross-Site Scripting (XSS). When user input is properly entity-encoded before being inserted into HTML, any malicious script tags become harmless text rather than executable code. However, context-aware encoding is essential — different contexts (HTML body, attributes, JavaScript, CSS) require different encoding strategies.

Switch to the Decode tab on this tool. Paste your entity-encoded string, and it will automatically convert all decimal, hexadecimal, and named entities back to their original characters. In JavaScript, you can also use the browser's native parser: create a textarea element, set its innerHTML to the entity string, and read its value — the browser handles all entity resolution automatically.

Yes. Numeric character references (both decimal A and hexadecimal A) are part of the HTML specification since HTML 4.01 and are supported by every modern and legacy browser. Named entities like & and € are also universally supported. For maximum compatibility, numeric entities are preferred, as some older browsers had gaps in named entity support for less common symbols.

HTML entities work in any context that renders HTML, including emails (when sent as HTML email), web pages, and many content management systems. However, they do not work in plain text emails, SMS messages, or non-HTML contexts — in those cases, the entity codes will appear literally. For plain text, use the actual Unicode characters or appropriate encoding (like UTF-8) instead.

HTML5 defines approximately 2,000+ named character entities. The most common include: & (&), < (<), > (>), " ("), ' ('),   (non-breaking space), © (©), ® (®), € (€), — (—), and many Greek letters, math symbols, arrows, and Latin-1 accented characters. This tool's "Named Priority" format uses named entities whenever available and falls back to hexadecimal for all other characters.

Each character converted to an entity expands from 1 character to 4–10+ characters. For example, A (1 byte) becomes A (5 bytes) in decimal or A (5 bytes) in hex. Named entities like € (6 bytes) replace € (3 bytes in UTF-8). The "Ratio" statistic in this tool shows the expansion factor. For short strings this is negligible, but for large documents, entity encoding can significantly increase file size. Use targeted encoding (Special Chars or Non-ASCII modes) to minimize bloat.

This tool correctly handles characters beyond the Basic Multilingual Plane (BMP), including emoji like 😀 (U+1F600), which require surrogate pairs in UTF-16. Rather than encoding each surrogate half separately, the tool uses the full Unicode code point — so 😀 becomes 😀 (decimal) or 😀 (hex), representing the complete character. This ensures proper round-trip conversion and display across all platforms.