URL Encoder / Decoder
URL Encoder / Decoder — runs in your browser. Inputs are not stored.
URL encode / decode
Uses encodeURIComponent / decodeURIComponent. Input is processed in the browser only.
How to use
- Paste a query value, Hangul, or a string with spaces and special characters into Input.
- Press Encode for percent-encoding that matches JavaScript
encodeURIComponent. - Values that are already in
%HHform can be restored with Decode. A plus sign (+) from forms is turned into a space before decoding. - Swap input/output moves the result back into input so you can convert again.
- Reset clears both fields. Values are processed only in this page’s browser and are not uploaded.
- When building search, redirect, or API queries, leave keys as they are, encode only the values, then join them with
&.
Key concepts
URL encoding (percent-encoding) turns characters that would break or change meaning in an address (spaces, Hangul, &, =, ?, and so on) into UTF-8 bytes such as %EC%95%88. This screen follows browser encodeURIComponent, so spaces become %20 rather than plus signs, which fits encoding a value for a path segment or query parameter. Reserved characters are escaped too, so encode value by value instead of running a finished URL through it.
Encoding a whole URL also escapes the colon and slashes in https://, so the browser cannot open it as a link. Decode uses decodeURIComponent, and plus signs common in form posts are replaced with spaces first. A truncated % sequence or invalid hex shows a failure message. Conversion uses only this tab’s JavaScript; input is not sent or stored.
Example
Encoding 안녕하세요 turns the UTF-8 bytes into %EC%95%88%EB%85%95%ED%95%98%EC%84%B8%EC%9A%94. hello world becomes hello%20world. When building a query such as q=검색어&sort=new, encode only 검색어 and append it after q=. Swap input/output and decode to confirm the original text comes back.
Related: Hash generator · Base64 → image · Character counter
Frequently asked questions
What is URL encoding?
It is the rule that turns characters unsafe in an address into <code>%</code> plus hex. It is almost required when sending Hangul, spaces, or reserved characters as search, redirect, or API query values.
What is the difference between encodeURIComponent and encodeURI?
This tool is value-oriented <code>encodeURIComponent</code>. <code>encodeURI</code> leaves colons, slashes, and question marks so you can handle a full URL at once, but it is a poor fit for parameter values.
Is a space %20 or + in the URL encoder?
Encode always produces <code>%20</code>. Only on decode is a plus from the <code>application/x-www-form-urlencoded</code> convention treated as a space.
Why should I not URL-encode an entire URL?
The protocol and path separators are escaped too, so the browser cannot open it as a link. Leave keys as they are, encode only values, then join with <code>&</code>.
When does URL decoding fail?
If what follows <code>%</code> is not hex, or a byte sequence is truncated, a failure message appears. Check whether spaces were mixed in when you copied the original.
Is URL encoder input sent to a server?
No. Conversion uses only this page’s browser JavaScript, with no upload or log storage.
Last reviewed: 2026-09-04