What this is
A URL can only carry a limited set of characters. Anything outside that set, such as a space or an ampersand, has to be rewritten as a percent sign followed by two hex digits. That rewriting is called percent-encoding, and it is what turns hello world into hello%20world.
This tool converts text in both directions. Paste something in, choose encode or decode, and read the result. Everything runs in your browser.
Where this is useful
You are debugging an API call and need to know what the server actually received after a query string was encoded.
You are building a link that carries a search term with spaces, quotes, or a plus sign, and you need the term encoded before you paste it into the URL.
You copied a long tracking link from an email and want to read the campaign parameters hidden behind %3F and %3D.
You received a redirect target that was encoded twice and want to peel it back one layer at a time.
How to use this tool
Paste or type your text into the input box. Pick a direction, Encode or Decode, using the buttons above the box.
Choose a scope. Component encodes every reserved character, which is what you want for a single query value or path segment. Full URL leaves the structural characters such as the slash, the question mark, and the ampersand alone, so a complete address stays usable.
The result appears below as you type. Copy it to your clipboard, or use Swap to move the result back into the input for another pass.
Frequently asked questions
What is the difference between Component and Full URL?
Component treats your text as one value, so characters like &, =, /, and ? are all encoded. Full URL assumes you handed it a whole address and preserves those characters, encoding only what would otherwise break the link. If you are encoding a single query parameter, pick Component.
Why do spaces sometimes become a plus sign instead of %20?
Older HTML form submissions encode a space as +, while percent-encoding uses %20. Both appear in the wild. This tool writes %20, and when decoding you can turn on the plus option so + is read back as a space.
What does it mean when decoding fails?
A percent sign must be followed by two valid hex digits. If the text contains a stray % or a truncated sequence, the decoder cannot tell what byte was intended, and the tool reports the input as malformed rather than guessing.
Is my text uploaded anywhere? No. The conversion happens entirely in your browser using built-in functions. Nothing leaves the page.