What's the difference between Component and Full URL encoding?

Component encoding (encodeURIComponent) escapes every reserved character, including / ? & = — use it for a single query string value. Full URL encoding (encodeURI) leaves URL structure characters like :, /, ?, and & untouched, so it's meant for encoding an entire URL you already have.

Why do spaces turn into %20?

Percent-encoding represents any character outside the URL-safe set as %XX, where XX is its byte value in hex. A space is byte 0x20, so it becomes %20 (some encoders use + instead, but %20 is the standard percent-encoding form used here).

Why does decoding sometimes fail?

Decoding fails when the input contains a % that isn't followed by two valid hex digits, or an incomplete multi-byte UTF-8 sequence — that means the text wasn't valid percent-encoded data to begin with.

Is my URL sent anywhere?

No. Encoding and decoding both run locally in your browser using JavaScript's built-in encodeURIComponent/decodeURIComponent — nothing is transmitted.

URL ENCODER / DECODER

Percent-encode text or a URL, or decode it back. Nothing leaves your browser.

Text / URL

Encoded

https%3A%2F%2Fexample.com%2Fsearch%3Fq%3Dhello%20world%26tag%3Da%20b

How to encode or decode a URL

1
Paste the text or URL you want to encode (or a percent-encoded string to decode).
2
Switch between Encode and Decode.
3
Choose Component to escape every reserved character, or Full URL to keep URL structure characters like / and : intact.
4
Copy the result.

Questions

What's the difference between Component and Full URL encoding?: Component encoding (encodeURIComponent) escapes every reserved character, including / ? & = — use it for a single query string value. Full URL encoding (encodeURI) leaves URL structure characters like :, /, ?, and & untouched, so it's meant for encoding an entire URL you already have.
Why do spaces turn into %20?: Percent-encoding represents any character outside the URL-safe set as %XX, where XX is its byte value in hex. A space is byte 0x20, so it becomes %20 (some encoders use + instead, but %20 is the standard percent-encoding form used here).
Why does decoding sometimes fail?: Decoding fails when the input contains a % that isn't followed by two valid hex digits, or an incomplete multi-byte UTF-8 sequence — that means the text wasn't valid percent-encoded data to begin with.
Is my URL sent anywhere?: No. Encoding and decoding both run locally in your browser using JavaScript's built-in encodeURIComponent/decodeURIComponent — nothing is transmitted.