URL Encoder & Decoder - Percent-Encoding Tool
Encode URL parameters and decode percent-escaped values without changing the structure of a full URL.
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Why URLs Need Encoding
URLs are built from reserved characters that have structural jobs — “?” starts the query string, “&” separates parameters, “=” joins a name to its value, “#” begins a fragment, and “/” divides path segments. When a parameter value contains one of those characters unescaped, the server reads it as structure rather than data: “?q=a&b=c” is parsed as two parameters even when the ampersand was meant to be part of the value. Percent-encoding fixes that by writing every unsafe byte as a “%” followed by two hexadecimal digits, so a space becomes %20 and a literal ampersand becomes %26.
Non-ASCII characters get the same treatment at the byte level: é, ñ, and emoji are encoded from their UTF-8 bytes into sequences such as %C3%A9. Decoding reverses the process, turning the percent-encoded triplets back into the original characters so the application receives the true value. Because the transformation works per character, this page can encode or decode a single query value, one path segment, or a whole string you want to inspect.
Spaces: %20 vs. +
Two conventions exist for spaces, and they are not interchangeable. Percent-encoding per the URL standard uses %20 — that is what encodeURIComponent() produces in JavaScript and what most modern APIs expect. HTML form data, sent as application/x-www-form-urlencoded, historically encodes a space as “+”, which is why query strings assembled by older forms can arrive with plus signs where spaces should be.
The split matters on decode. In a form-style value a “+” usually means a space; in a percent-encoded URI it is a literal plus sign. When the output looks wrong, check which convention the receiving endpoint expects and match it — %20 is the safer default for REST APIs and JavaScript clients, while “+” survives in legacy form handlers.
Questions fréquentes
Should I encode the whole URL or just the parameters?
Encode the individual parts, not the whole URL. The structural characters — the scheme separator, the “?”, “&”, and “=” that assemble the query string, and the “/” between path segments — must stay untouched or the address stops meaning the same thing to the server. Only the values traveling inside those parts need encoding: each query parameter value, and any path segment that may contain spaces, punctuation, or non-ASCII text. Encoding the entire URL turns the separators into %3A, %2F, and %3F, which many servers reject or route differently than the original address.
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