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URL Encode & Decode

Encode or decode URL components — component or full URL mode.

What is URL Encoding (Percent-Encoding)?

URL encoding, also called percent-encoding, is a mechanism for encoding characters in a Uniform Resource Identifier (URI). It replaces unsafe characters with a % sign followed by two hexadecimal digits representing the character's ASCII value.

For example, a space becomes %20, an ampersand becomes %26, and a question mark becomes %3F. This ensures URLs are valid and unambiguous, as defined by RFC 3986.

How to Use This Tool

  1. Select Encode or Decode mode
  2. Paste your text or URL in the input field
  3. The encoded/decoded result appears instantly
  4. Click Copy to copy the result

Characters That Must Be Encoded

The following characters have special meaning in URLs and must be percent-encoded when used as data:

  • space → %20 — Spaces are not valid in URLs
  • & → %26 — Separates query parameters
  • = → %3D — Separates key=value pairs
  • # → %23 — Fragment identifier

Frequently Asked Questions

What is URL encoding?
URL encoding (percent-encoding) converts special characters into a format that can be transmitted in URLs. Characters like spaces, &, =, and non-ASCII characters are replaced with a % sign followed by their hexadecimal value.
What is the difference between component and full URL encoding?
Component encoding (encodeURIComponent) encodes everything except letters, digits, and - _ . ~ — use this for query parameter values. Full URL encoding (encodeURI) preserves URL structure characters like :, /, ?, #, and & — use this for complete URLs.
Why do spaces become %20 or +?
In URLs, spaces are encoded as %20 (RFC 3986 standard). In HTML form data (application/x-www-form-urlencoded), spaces become +. Both represent a space, but %20 is the correct encoding for URL paths and query parameters.
Is my data sent to a server?
No. All encoding and decoding happens in your browser using JavaScript. Your data stays on your device.
When should I URL-encode data?
Always encode user input before putting it in URLs — query parameters, path segments, and fragment identifiers. This prevents broken URLs and protects against injection attacks.
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