URL Encoder / Decoder
Encode and decode URL percent-encoding in real time.
Perfect for building query parameters and analyzing URLs.
What is URL Encoder / Decoder?
A free online tool that converts special characters in URLs — such as spaces, Japanese text, and symbols — into RFC 3986-compliant percent-encoding (%XX format). You can also decode encoded URLs back to readable strings.
Supports both encodeURIComponent and encodeURI modes, making it ideal for building API query parameters or verifying SEO-friendly URLs. All processing is done locally in your browser.
How to Use
Select Mode
Choose either "Encode" or "Decode" mode using the toggle buttons.
Enter Text
Paste your URL or string into the left textarea. Results appear on the right in real time.
Copy & Use
Click the Copy button to copy the result to your clipboard. Use Swap to reverse input and output.
Glossary
- Percent-Encoding
- A method of encoding characters that cannot be used in URLs into %XX format (XX is hexadecimal). Defined in RFC 3986.
- encodeURIComponent
- JavaScript function that encodes all special characters including /, ?, and &. Used for query parameter values.
- encodeURI
- JavaScript function that leaves URL structural characters (/, :, ?, #, &) unencoded while encoding everything else.
- UTF-8
- Unicode encoding format. One Japanese character is encoded as 3 bytes (e.g., %E6%9D%B1).
- RFC 3986
- Internet standard defining URI syntax, including the distinction between reserved and unreserved characters.
- Query String
- The part of a URL after ? containing key=value parameters joined by &.
- Fragment
- The part of a URL after # that specifies an in-page anchor.
FAQ
- Q.What is the difference between encodeURIComponent and encodeURI?
- encodeURIComponent encodes all special characters including /, ?, and &. encodeURI leaves URL structural characters intact and only encodes non-ASCII characters.
- Q.Is my URL data sent to a server?
- No. All conversions are performed entirely in your browser using JavaScript's built-in functions.
- Q.What happens when I encode Japanese text?
- The text is encoded in UTF-8, converting each Japanese character to a three-byte percent-encoded sequence like %E6%9D%B1.
- Q.What if decoding fails?
- An error occurs if the input contains invalid percent-encoding sequences (e.g., %ZZ). Please verify your input.
- Q.Can I encode Base64 here?
- This tool is specifically for URL percent-encoding. Please use a dedicated Base64 tool for Base64 encoding.
Use Cases
🔧 API Development
Verify encoding of Japanese or special characters in query parameters.
🔍 SEO & Link Audit
Decode encoded URLs to confirm they point to the intended content.
📧 Email & Chat
Decode encoded URLs received in emails or messages.
📊 Analytics Logs
Decode percent-encoded URL parameters in server access logs.