URL Encoder and Decoder – Percent-Encode and Decode URLs

How to use the URL encoder and decoder

1. Choose Encode or Decode.
2. Paste your text or URL.
3. When encoding, choose Query value, Whole URL or Form data.
4. When decoding, choose whether + means a space.

If the decoded text is a URL with a query string, a table lists each parameter and its value.

Which encoding to choose

• Query value (encodeURIComponent) — for one piece of data that goes inside a URL, such as a search term: q=café & crème → q=caf%C3%A9%20%26%20cr%C3%A8me.
• Whole URL (encodeURI) — for a full URL that contains spaces or non-ASCII characters but whose structure must stay intact.
• Form data — like a query value, but spaces become +, as in HTML form submissions.

Worked example

Encoding the value a b&c=d/é as a query value gives a%20b%26c%3Dd%2F%C3%A9. Each reserved character — space, &, =, / — is replaced, and é becomes two bytes, %C3 and %A9.

Reserved and unreserved characters

URLs give some characters special jobs: ? starts the query, & separates parameters, = joins names to values, # starts a fragment and / separates path segments. If your data contains these characters, they must be encoded so they aren’t mistaken for structure. Letters, digits and - _ . ~ never need encoding.

Common uses

• Building links with search terms, email addresses or redirects in the query string.
• Reading tracking links and long marketing URLs.
• Debugging APIs where parameters arrive encoded.
• Creating mailto: links with a subject and body.
• Fixing broken links that contain spaces or special characters.

Double encoding

Double encoding usually happens when a framework encodes a value automatically and the code encodes it again by hand.

A frequent bug is encoding something twice, so a space becomes %2520 (the % itself encoded as %25). If you see %25 followed by two hex digits in a URL, the value has probably been encoded twice — decode it once more.

Encoding in code

In JavaScript, use encodeURIComponent() for values and new URLSearchParams() to build query strings — it handles encoding for you. In Python, use urllib.parse.quote() and urlencode(); in PHP, rawurlencode() and http_build_query(). Building URLs by joining strings by hand is the most common cause of broken links and security bugs, because a value containing & or # can change the meaning of the whole URL.

The decoder is also useful for reading redirect and tracking links: decode them to see where a link really goes before you click it.

Related tools

For readable URL slugs from titles, see the slug generator. To encode data in Base64, use the Base64 encoder; for HTML special characters, the HTML entity encoder.