Percent-encode text for safe use in URLs and query strings, or decode it back.
This free tool percent-encodes text using JavaScript's encodeURIComponent (and decodes with decodeURIComponent) entirely in your browser — the correct choice for safely embedding a value inside a URL query string or path segment.
Characters outside the small set considered "safe" in a URL — letters, digits, and a handful of punctuation marks (- _ . ! ~ * ' ( )) — are converted to a % followed by two hex digits representing the character's UTF-8 byte value. A space becomes %20, & becomes %26, and so on.
encodeURIComponent (used by this tool) escapes every reserved character, including &, =, ?, and /, which makes it correct for encoding a single value that will be inserted into a query string or path segment. encodeURI leaves those structural characters alone because it's meant to encode an entire, already-structured URL rather than one piece of it — using it on a query value would leave & and = unescaped and break the URL's structure.
Any time you're building a URL programmatically and inserting user input, search terms, or data containing spaces, punctuation, or non-ASCII characters into a query string (?q=...) or path — encoding prevents the URL from breaking or being misparsed by the browser or server.
Percent-encoding converts unsafe characters (spaces, &, ?, #, non-ASCII) into a % followed by two hex digits, so they can be safely included in a URL.
encodeURIComponent escapes all reserved characters (&, =, ?, /) for encoding one value in a query string. encodeURI leaves those alone since it encodes a whole, already-structured URL.
Inside an application/x-www-form-urlencoded query string, + conventionally means space. Outside that context, %20 is correct — this tool uses the standard %20 form.
URLs only support a limited character set directly. Anything else must be percent-encoded or the URL may break or be misinterpreted.