Overview
Links break for silly reasons. A space in a filename, an accented letter in a name, a & inside a search term — each one is harmless to humans and poison to a URL parser. Percent-encoding is the agreed fix: replace the offending byte with % and two hex digits. This tool applies that fix in the mode your situation actually needs.
That last part matters more than it sounds. Encoding a whole address and encoding one query value are different operations with different rules — mix them up and you encode the ? and & that hold the URL together. The three modes here keep the jobs separate: full URL, single component, and decode.
What does percent-encoding do?
It rewrites any byte a URL cannot contain as a % sign followed by two hexadecimal digits. A space becomes %20, é becomes %C3%A9 (two bytes in UTF-8, hence two triplets). The result is pure ASCII, which every server, browser and email client on earth can transport without mangling.
The subtlety is which characters to leave alone. In a full URL, structural characters like : / ? & = must survive — they are the grammar of the address. Inside a single value, those same characters are data and must be encoded. That is why encodeURI and encodeURIComponent exist as separate functions, and why this tool exposes both.
Features
- Three dedicated modes: full URL, single component, and decode — each with the correct rules.
- Live encoding as you type, with no button to press and no page reload.
- Standard functions under the hood: the browser's own encodeURI / encodeURIComponent, not a hand-rolled approximation.
- UTF-8 aware: accents, non-Latin scripts and emoji encode to the right byte sequences.
- Reference table of the codes people look up most, built into the page.
- One-click copy of the result for pasting into code or links.
- Decode mode reverses either encoding, turning %20 back into a space.
- Private by design: everything runs locally in your browser.
Benefits
- Stop breaking links. The right mode encodes structure and data correctly every time.
- Debug faster. Paste a mangled URL into decode and see what it was meant to say.
- Learn the difference. Separate modes teach when each rule applies.
- Works offline once the page has loaded.
Who can use it
Web developers building query strings and APIs, marketers assembling tracked campaign links, support staff untangling broken URLs customers paste into tickets, and students learning how the web actually transports text. Anyone who has ever seen %20 in an address bar and wondered what happened will get something from the decode mode alone.
How to use
- Choose Full URL to encode a complete address, Component for a single value, or Decode to reverse.
- Paste or type your text into the input box.
- Read the encoded result as it updates live below.
- Check the reference table if you want to see what individual characters become.
- Press copy and paste the result wherever the URL needs to go.
Frequently asked questions
When should I use full-URL mode vs component mode?
Use full-URL mode when the whole address needs encoding but its structure must survive — the ?, & and = that separate parameters stay intact. Use component mode for a single value you are placing inside a URL, like a search term or a name: there, even & and = are data and must be encoded, or they will be misread as structure.
Why does a space sometimes become %20 and sometimes +?
Both are historical conventions. %20 is the proper percent-encoding for a space in a URL path. The + form comes from HTML form submissions (application/x-www-form-urlencoded), where spaces in form data are sent as +. They mean the same thing in query strings, but %20 is the safer, more universal choice.
Do I need to encode non-English characters?
Yes. URLs are officially ASCII-only, so characters like é, 中 or emoji must be encoded as their UTF-8 bytes. Modern browsers often display the pretty form while sending the encoded form behind the scenes — this tool shows you the encoded form explicitly, which is what servers actually receive.
Can encoding break a URL that already works?
Double-encoding can: encoding %20 again gives %2520, which decodes to the literal text %20 instead of a space. If a URL already contains % triplets, decode it first or encode only the unencoded parts. The decode mode exists precisely for inspecting such URLs.
Is what I paste sent anywhere?
No. Encoding is pure string arithmetic done in your browser. URLs often contain tokens and private parameters, so the tool was built to never transmit them.
Conclusion
Percent-encoding is a small discipline with an outsized payoff: pick the right mode for the job, let the tool do the byte work, and your links will survive every server, inbox and chat app they pass through.