What is the difference between "Part of a URL" and "Whole URL"?

Part of a URL (encodeURIComponent) also escapes / ? & = # and other reserved characters, which is what you want for a single query value or path segment. Whole URL (encodeURI) leaves those characters alone so the link still works, and escapes only spaces and other unsafe characters.

Why does decoding show an error?

Decoding fails when a % isn't followed by two hex digits, or when the escaped bytes don't form valid UTF-8, for example a truncated %C3. Fix or remove that sequence and the result appears.

Are plus signs decoded as spaces?

No. A + is kept as +. Only %20 becomes a space. Some forms write spaces as +, so replace those before decoding if that's what you have.

How are spaces and accented characters encoded?

A space becomes %20, and non-ASCII characters are encoded as UTF-8 bytes. For example, é becomes %C3%A9.

Encode and decode URLs for free in your browser

Percent-encode or decode a whole URL or one part of it, such as a query value, as you type.

How to use URL Encoder & Decoder

Choose Encode or Decode, and whether the input is part of a URL or a whole URL.
Type or paste your text, then copy the result.

Questions

What is the difference between "Part of a URL" and "Whole URL"?: Part of a URL (encodeURIComponent) also escapes / ? & = # and other reserved characters, which is what you want for a single query value or path segment. Whole URL (encodeURI) leaves those characters alone so the link still works, and escapes only spaces and other unsafe characters.
Why does decoding show an error?: Decoding fails when a % isn't followed by two hex digits, or when the escaped bytes don't form valid UTF-8, for example a truncated %C3. Fix or remove that sequence and the result appears.
Are plus signs decoded as spaces?: No. A + is kept as +. Only %20 becomes a space. Some forms write spaces as +, so replace those before decoding if that's what you have.
How are spaces and accented characters encoded?: A space becomes %20, and non-ASCII characters are encoded as UTF-8 bytes. For example, é becomes %C3%A9.

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