Conversion

URL Encoder / Decoder

Percent-encode or decode a UTF-8 URI component using JavaScript encodeURIComponent and decodeURIComponent. Use it for a query value or other component, rather than assuming it preserves a complete URL.

Input Text*

Conversion Mode*

Real-time Results

Result Output

Process completed successfully.

https%3A%2F%2Fcalnex.pro%2Fsearch%3Fquery%3Dhello%20world!

Why Choose URL Encoder / Decoder

How to Calculate

1Enter the component to process, such as hello world.
2Choose Encode to obtain hello%20world, or Decode to reverse valid percent encoding.
3Insert the result in the appropriate URL component; verify the complete URL separately.

Frequently Asked Questions (FAQ)

Why does a complete URL lose its separators?

encodeURIComponent encodes reserved separators such as : / ? & and =. It is intended for components. Encoding a complete URL with it changes the structure rather than simply replacing spaces.

Does a plus sign decode to a space?

No. decodeURIComponent leaves + as +. Form-encoded query strings can use + for spaces, which requires form parsing rather than plain component decoding.

What does a decoding error mean?

An incomplete percent escape or invalid UTF-8 byte sequence cannot be decoded. The tool returns an error instead of guessing the original text.

Authoritative References & Sources

MDN — encodeURIComponent

View Source

Calculation Principles & Mathematical Formula

URL Encoding Rules:
1. URL Encoding converts characters into a format that can be transmitted over the Internet safely.
2. Standard characters like letters and numbers are left unchanged.
3. Special characters (e.g. space, ?, =, &) are converted to a "%" followed by two hexadecimal digits representing their UTF-8 byte values (e.g. space becomes "%20").
4. decodeURIComponent() translates escape sequences back into their original UTF-8 characters.

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