What is URL Encoder / Decoder?
The URL Encoder / Decoder percent-encodes and decodes text so it can be placed safely in a URL. Percent-encoding, defined in RFC 3986, replaces characters that are reserved or unsafe in URLs with a % followed by their byte value in hexadecimal — for example, a space becomes %20.
By default the tool encodes components (like a single query value or path segment) using encodeURIComponent, which escapes reserved characters such as & = ? / and #. Decoding uses decodeURIComponent and also converts + to a space, matching how form submissions encode spaces.
It runs entirely in your browser.
Why Use This Tool?
Placing raw text into a URL breaks it when the text contains reserved characters. Encoding query values and path segments keeps links valid and prevents parameters from being misparsed or truncated.
- Safely embed values in query strings and paths.
- Decode parameters you receive to read their real content.
- Handle spaces, ampersands, and Unicode correctly.
- Avoid broken or ambiguous URLs.
How Does This Tool Work?
In component mode, encoding calls encodeURIComponent, which escapes every character except the URI-unreserved set, so reserved delimiters inside a value are preserved as data rather than interpreted as structure. A whole-URL mode uses encodeURI, which leaves reserved delimiters like :/?#& intact so the overall URL still functions.
Decoding first replaces + with a space (the application/x-www-form-urlencoded convention) and then applies decodeURIComponent to turn percent-escapes back into their original characters.
Understanding Your Results
Encoded output contains %XX sequences for each escaped byte; UTF-8 characters expand into multiple percent-escapes. Decoded output restores the original text. If decoding throws, the input contains a malformed percent-escape (for example a lone % not followed by two hex digits).
Choosing the wrong mode is the usual pitfall: encode individual values with component mode, and reserve whole-URL mode for an entire address you do not want to break apart.
Why Tracking This Matters
Query strings drive search, filters, tracking, and API calls. Correct encoding keeps user input, tokens, and special characters intact end-to-end, avoiding subtle bugs where an unescaped & silently splits one parameter into two.
Benefits of Using URL Encoder / Decoder
- Component and whole-URL modes
- Correct UTF-8 percent-encoding
- Handles the + as space convention on decode
- Prevents broken or ambiguous URLs
- Reversible, lossless conversion
- Runs privately in your browser
How Is the Result Calculated?
Percent-encoding maps each byte that must be escaped to a three-character sequence: % plus two uppercase hex digits. Multi-byte UTF-8 characters produce one escape per byte, so a single emoji may expand into four %XX sequences.
escaped byte → %XX (two hex digits)
Tips for Better Results
- Encode values, not the whole URL, unless you specifically want whole-URL mode.
- Remember + decodes to a space in form-encoded query strings.
- Encode each query parameter separately, then join with & and =.
- Watch for double-encoding — encoding an already-encoded value escapes the % signs.
- Use the URL Parser to inspect a full URL's components.
Standards and References
Conclusion
The URL Encoder / Decoder applies RFC 3986 percent-encoding so values travel safely inside URLs, with sensible handling of the + as space convention on decode.
Encode individual components by default, reserve whole-URL mode for complete addresses, and avoid double-encoding.