Putting a link inside a query parameter
A redirect target has to be encoded in value mode, otherwise its own query string merges into the outer one and the redirect goes somewhere unexpected.
URL Encoder and Decoder
Percent-encode and decode URLs in your browser, choosing between encoding a value inside a URL and encoding a whole address.
Maintained by Roshan.
Use URL Encoder and Decoder
Percent-encoding, done in the tab. Component mode escapes the separators that structure a URL; full-address mode leaves them alone.
Picking the wrong mode is the usual bugEncoding a whole address as a component escapes its own slashes and question mark. Encoding a value as a full address leaves & and = intact, so an embedded link splits into extra query parameters.
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Browse all developer and data toolsAbout URL Encoder and Decoder
Percent-encoding looks like one operation and is actually two, which is why so many broken links trace back to it. Encoding a value that will sit inside a URL must escape the characters that give a URL its structure. Encoding an entire address must leave those same characters alone, or the address stops working. Pick the wrong one and the failure is quiet: the string looks encoded, the request goes out, and the server receives something subtly different from what you meant. This page keeps the two modes separate, names them in plain language, and shows exactly which characters they disagree about.
Using URL Encoder and Decoder
- Choose whether you are handling a value that goes inside a URL or a complete web address. The labels avoid the function names deliberately, because remembering which of two near-identical names does what is the actual difficulty.
- Value mode escapes the reserved characters that structure a URL, including the ampersand, equals sign, question mark, slash, and hash. That is what makes it safe to drop an arbitrary string into a query parameter.
- Address mode leaves those separators intact and escapes only what is never legal in a URL, such as spaces and quotation marks. Use it when you have a whole link that merely needs tidying.
- Decoding reverses either mode. If the text contains a stray percent sign that is not part of a valid escape, the tool says so rather than returning something mangled - an unpaired percent is the most common cause of a decode failure.
Where url encoder and decoder helps
Cleaning up a pasted address
An address copied from a document often contains spaces. Address mode escapes those and leaves the structure intact, so the link works.
Reading an encoded string from a log
Decoding turns a wall of percent escapes back into readable text, which makes it obvious what a request actually carried.
Diagnosing double encoding
Decode once and look at the result. If it still contains percent escapes, it was encoded twice somewhere upstream.
Before you use the result
- Encoding a whole address in value mode is the classic mistake. Its slashes, colon, and question mark all get escaped, producing a string that is technically valid and completely useless as a link.
- Encoding a value in address mode is the mirror image, and worse because it usually appears to work. Ampersands and equals signs survive, so an embedded link inside a query parameter silently splits into extra parameters and the receiving server sees a different request than you intended.
- A space can legitimately appear as either %20 or a plus sign, depending on context. Percent-encoding uses %20; the plus form comes from HTML form submission. This tool always produces %20, which is safe in a path or a query, but be aware that some systems expect the other.
- Encoding twice is not harmless. A percent sign is itself escaped to %25, so running an already-encoded string through again turns %20 into %2520. If your output looks like it has extra 25s in it, something in the chain is encoding a second time.
Questions about URL Encoder and Decoder
Is my text sent anywhere?
No. Encoding and decoding both run in your browser using standard string functions. Nothing is transmitted, which matters because URLs frequently contain tokens and identifiers.
Which mode do I want?
If the string will be placed inside a larger URL, choose value mode. If the string is itself a complete address, choose address mode. When unsure, look at the list of differing characters shown with the result.
Why did my decode fail?
Almost always an unpaired percent sign. A literal percent in text must itself be written as %25; otherwise the decoder reads the next two characters as a hex code and gives up when they are not.
Should a space be %20 or a plus?
%20 is correct percent-encoding and works in both paths and query strings. The plus form comes from HTML form encoding and is only understood in a query string, so %20 is the safer default.
What causes %2520 to appear?
Double encoding. A space became %20, then that string was encoded again, turning its percent sign into %25. Find the step that encodes twice rather than trying to fix the output.
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