OptiDrop

URL Encoder & Decoder Online — Percent Encoding & HTML Entities Free

Encode and decode URLs with percent encoding. Convert HTML entities. Instant processing, copy to clipboard. No upload, 100% private.

Characters: 0
Output will appear here...
Output characters: 0
Characters: 0
Output will appear here...
Output characters: 0

Free Online URL Encoder & Decoder

OptiDrop's URL Encoder/Decoder lets you encode and decode URLs using percent encoding, and convert HTML entities. This is essential for web developers working with query strings, API requests, and HTML content that contains special characters.

Percent Encoding (URL Encoding)

URL encoding replaces unsafe ASCII characters with a percent sign (%) followed by two hexadecimal digits. Spaces become %20, ampersands become %26, and so on. This ensures URLs remain valid when they contain characters that have special meaning in URLs or are not allowed in certain URL components.

HTML Entity Encoding

HTML entity encoding converts special HTML characters into their entity equivalents. For example, the less-than sign (<) becomes &lt; and the ampersand (&) becomes &amp;. This is critical for safely displaying user-generated content on web pages and preventing cross-site scripting (XSS) attacks.

Instant Processing

All encoding and decoding happens instantly in your browser. No data is sent to any server. Results are processed in real time and can be copied to clipboard with one click.

Frequently Asked Questions

URL encoding (also called percent encoding) is a mechanism for encoding unsafe or reserved characters in a URL by replacing them with a percent sign (%) followed by two hexadecimal digits. For example, a space becomes %20, and an ampersand (&) becomes %26.
Percent encoding is the technical term for URL encoding. Each character that needs encoding is replaced with a percent sign followed by its ASCII hexadecimal value. Characters that are safe in URLs (letters, digits, hyphens, underscores, periods, tildes) are left unchanged.
You need to encode a URL when it contains special characters such as spaces, ampersands, question marks, or non-ASCII characters. This is especially important for query parameters in URLs, form submissions, and API requests where special characters could break the URL structure.
HTML entity encoding replaces special HTML characters with their entity representations. For example, < becomes &lt;, > becomes &gt;, & becomes &amp;, and " becomes &quot;. This prevents browsers from interpreting these characters as HTML code and is essential for preventing XSS attacks.

Last updated: June 2026