How to use this tool
- Enter the source in the input field.
- Choose URL component, Complete URI or Form value and select encode or decode.
- Valid input updates after a brief typing pause. You can also use the main action button. Resolve errors before copying or downloading.
- Clear input keeps the conversion settings; Undo input change restores the previous inputs after clear or reverse. Reset restores the example and default settings.
Understanding the output
Encoding protects characters that could otherwise act as URL separators. A space becomes %20 and an ampersand becomes %26. Decoding reverses valid percent-encoded UTF-8 sequences. A plus sign stays a plus unless the explicit form-style option is enabled.
To inspect the parts of a complete address, use the URL Parser rather than encoding the entire URL as one component.
A query value containing an ampersand
tea & coffee becomes tea%20%26%20coffee. The encoded ampersand belongs to the value rather than separating it into two query parameters. Form encoding a+b c produces a%2Bb+c. Reversing it returns a+b c.
Encode values, not an entire address blindly
A complete URL contains structural characters such as a colon, slashes, a question mark, and ampersands. Encoding all of them as one component changes the address into a value that could be embedded somewhere else. When building a query string, encode each value at the appropriate boundary or use a URL API that manages those boundaries for you.
Encoding a value twice changes percent signs to %25 and can produce unexpected server-side results. Check whether the value has already been encoded before applying another conversion. The tool does not automatically guess the intended number of decoding passes.
Distinguish percent encoding from form encoding
In common form-style query serialization, a space can be represented by a plus sign. In a path or an arbitrary component, that same plus may be literal text. The decoding option exists because both conventions are encountered in practice. Choose it based on the source format, not simply because the decoded phrase looks more readable.
Method and supported input
Component mode uses encodeURIComponent/decodeURIComponent. URI mode retains structural delimiters and reserved encoded separators during decoding. Form-value mode encodes spaces as + and decodes + as spaces; malformed percent escapes still fail.
- The input represents a component or value rather than a complete URL structure.
Limitations
- Encoding does not validate a destination or make a URL safe to visit.
- Legacy non-UTF-8 encodings are not supported.
Common questions
Should I paste the whole URL into encode mode?
Choose Complete URI to retain its structural separators. Choose URL component when the entire URL needs to be one encoded value inside another URL. This tool does not validate destinations.
Why does decoding fail on a lone percent sign?
A percent sign begins an escape and must be followed by two hexadecimal digits representing a byte.
Sources and further reading
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