The HTML entities are used to display reserved characters (characters that are used in HTML code), special characters, or invisible characters. For example,
<p>This is a <p> tag.</p> 
Browser Output
Here, < and > are the HTML entities used to display < and > respectively. 
If we were to use the <p> tag instead of <p> the browser would read it as a tag. Hence to display <p> we need to use < and > instead of < and > respectively.
HTML Entities Syntax
HTML entities are represented by either their name or their number.
- Entity names
 
We use &entity_name; to add reserved characters using Entity names. For example,
¢ would be displayed as ¢
- Entity number
 
We use &#entity_number; to add reserved characters using Entity number. For example, ¢ would also be displayed as ¢
All entity names and numbers start with an & and end with an ;.
Note: Not all entities have names, only characters that are commonly used have entity names.
Special Characters
Special characters are characters that are not available on a general keyboard like ®, ©, ¢, etc. 
We use HTML entities to add special characters to HTML documents. For example
<footer> © 2022 Programiz. All rights reserved. </footer>
Browser Output
Invisible Characters
An invisible character is a character that is not visible when rendered in a document or text field. These characters can be used for various purposes, such as adding white space or formatting a document. For example,
<p>Invi<span>‌</span>sible<span> </span>Cha<span>‌</span>racters</p>
Browser Output
Here, ‌ and   are invisible characters. ‌ is a zero-width character whereas   is a space character.
Some examples of invisible characters are – space, tab, zero-width space, etc.
Some important HTML entities
| Character(s) | Literal(s) | Alphanumeric value(s) | Unicode value(s) | 
|---|---|---|---|
| Cent (currency) | ¢ | 
¢ | 
¢ | 
| Pound (currency) | £ | 
£ | 
£ | 
| Section | § | 
§ | 
§ | 
| Copyright | © | 
© | 
© | 
| Guillemets | « » | 
« » | 
« » | 
| Registered trademark | ® | 
® | 
® | 
| Degree(s) | ° | 
° | 
° | 
| Plus/minus | ± | 
± | 
± | 
| Pilcrow (paragraph) | ¶ | 
¶ | 
¶ | 
| Middle dot | · | 
· | 
· | 
| Fractional half | ½ | 
½ | 
¼ | 
| En dash | – | 
– | 
– | 
| Em (long) dash | — | 
— | 
— | 
| Single quotes | ' ' | 
‘ ’ | 
‘ ’ | 
| Single low quote | ‚ | 
‚ | 
‚ | 
| Double quotes | " " | 
“ ” | 
“ ” | 
| Double low quote | „ | 
„ | 
„ | 
| Single & double daggers | † ‡ | 
† ‡ | 
† ‡ | 
| Bullet | • | 
• | 
• | 
| Ellipsis | … | 
… | 
… | 
| Prime & double prime | ′ ″ | 
′ ″ | 
′ ″ | 
| Euro sign | € | 
€ | 
€ | 
| Trademark | ™ | 
™ | 
™ | 
| Almost equal to | ≈ | 
≈ | 
≈ | 
| Not equal to | ≠ | 
≠ | 
≠ | 
| Less/greater than or equal to | ≤ ≥ | 
≤ ≥ | 
≤ ≥ | 
| Less/greater than | < > | 
< > | 
> < |