URL エンコード/デコード

What is URL Encoder / Decoder?

URL Encoder / Decoder converts special characters in URLs to percent-encoded format (e.g. spaces become %20) and decodes percent-encoded strings back to readable text. Proper URL encoding ensures that query parameters and path segments are transmitted correctly by browsers and servers.

How to use

1. To encode: paste a string with special characters and click Encode.
2. To decode: paste a percent-encoded string and click Decode.
3. Copy the result with the Copy button.

Notes

• This tool encodes component parts of a URL (e.g. query values), not full URLs. Encoding a full URL would break the :// and / delimiters.
• Safe characters (letters, digits, -, _, ., ~) are not encoded.
• Spaces can be encoded as %20 (RFC 3986) or + (form encoding). This tool uses %20.

FAQ

What is the difference between encodeURI and encodeURIComponent?

encodeURI encodes a full URL and leaves structural characters like /, ?, and # intact. encodeURIComponent encodes a URL component (query value, path segment) and percent-encodes those structural characters. This tool uses encodeURIComponent behavior.

Why do I need to encode URL parameters?

Characters like &, =, and spaces have special meaning in URLs. If a query value contains those characters without encoding, the URL is misinterpreted by the server.

Can I encode non-ASCII characters?

Yes. Non-ASCII characters (like Japanese or Arabic letters) are first converted to UTF-8 bytes, then each byte is percent-encoded.