URL Encode / Decode

About URL encoding

Percent-encoding replaces characters that are not allowed (or have special meaning) in a URL with a %XX hex sequence. Component mode usesencodeURIComponent, which encodes everything except letters, digits, and - _ . ! ~ * ' ( ) — use this for individual query-string values. Full URI mode uses encodeURI, which preserves the structural characters (: / ? # [ ] @ ! $ & ' ( ) * + , ; =) — use this when encoding a complete URL.

When to use it

Any time you build a URL from data you did not type yourself. Search terms, free-text filters, file names, redirect targets, and values pulled from a database all need encoding before they go into a query string or path segment, otherwise a space, an ampersand, or a slash silently breaks the URL. This is also the tool for decoding the %20,%2F, and %C3%A9-style strings you see in logs, analytics dashboards, and share links.

How this tool works

Conversion uses the browser's native encodeURIComponent /decodeURIComponent andencodeURI / decodeURIfunctions, so the result matches exactly what your own JavaScript would produce. Non-ASCII characters are first converted to UTF-8 bytes, so €becomes the three-byte escape %E2%82%AC.

Edge cases and limitations

The most common mistake is picking the wrong mode. Encoding a whole URL in Componentmode turns every slash into %2F and breaks it; encoding only a query value in Full URI mode leaves the dangerous characters untouched. Watch for double encoding: if the input already contains escapes, re-encoding turns the% into %25 — decode once, then re-encode. Decoding a malformed sequence throws an error that this tool surfaces as Invalid percent-encoding. Note that this tool emits %20for spaces, not the + used by older form-encoding.

Example

hello world in Component mode becomeshello%20world, whilea/b?c=d stays intact in Full URI mode.

Related tools

For binary data that must survive a URL, use the Base64 encoderin URL-safe mode instead of percent-encoding. For escaping text destined for HTML or XML markup rather than a URL, see the HTML encoder.