URL Encoder

What is URL encoding?

URL encoding, also known as percent-encoding, is the standardised way of representing characters that are not allowed or not safe inside a URL. Because URLs may only contain a limited subset of ASCII characters — letters, digits and a few reserved symbols such as -, _, ., ~ — any other character must be encoded as a percent sign followed by two hexadecimal digits that represent the byte value. A space, for example, becomes %20, an ampersand becomes %26, and the Chinese character 你 becomes %E4%BD%A0 in UTF-8.

URL encoding was first formalised in RFC 1738 in 1994 and is currently specified in RFC 3986. It is what allows browsers, web servers, and HTTP clients to exchange data containing Unicode characters, spaces, punctuation and reserved symbols without ambiguity. Every modern programming language ships with a built-in URL encoder, and the JavaScript function used by this tool is encodeURIComponent().

When to URL-encode text

URL encoding is needed whenever you place text data inside a URL — most commonly in query strings, path segments, fragment identifiers, form payloads, or HTTP headers. Common scenarios include:

• Query parameters. When appending ?name=John Doe&city=New York to a URL, the spaces and special characters must be percent-encoded to ?name=John%20Doe&city=New%20York.
• API requests. REST and GraphQL APIs expect encoded values in their URLs; an unencoded / in a parameter could be misinterpreted as a path separator.
• Email and messaging links. Mailto links, share URLs and deep links must encode subject, body and parameter values.
• Non-ASCII text. Chinese, Japanese, Korean, Arabic and emoji characters must be percent-encoded in UTF-8 to be safely included in a URL.
• OAuth and SSO callbacks. State tokens, redirect URIs and code challenges are transmitted as encoded query parameters.
• Analytics tracking. UTM parameters containing spaces, ampersands or accented letters must be encoded to survive transport.

Forgetting to encode a value can break a URL, leak partial data to the wrong parameter, or trigger 400 Bad Request responses from strict servers.

encodeURIComponent vs encodeURI

JavaScript provides two related encoding functions, and choosing the wrong one is a common source of bugs. encodeURIComponent() is intended for individual parameter values and encodes every reserved character except A–Z, a–z, 0–9, and - _ . ~. encodeURI() is intended for whole URLs and leaves the structural separators : / ? # [ ] @ ! $ & ' ( ) * + , ; = untouched so the URL keeps working.

As a rule of thumb, use encodeURIComponent() for each value you drop into a query string, path segment or form field. Use encodeURI() only when you are encoding a complete, already-structured URL and want to keep its syntax intact. This tool uses encodeURIComponent() because the most common real-world task is encoding a single value rather than a full URL.

Common URL-encoded characters

Familiarising yourself with the most common encoded forms speeds up debugging of malformed URLs. The table below lists characters that are encoded most often in practice.

Character	Encoded	Why
Space	%20	Spaces are not allowed inside URLs
&	%26	Separates query parameters
=	%3D	Separates keys from values
?	%3F	Marks the start of the query string
#	%23	Marks the start of the fragment
/	%2F	Path separator
+	%2B	Decoded as space in form data
%	%25	Escape character itself

Note that in application/x-www-form-urlencoded payloads (HTML form submissions), a space is encoded as + rather than %20. Both forms are valid in URLs, but %20 is the canonical percent-encoding.

How to encode a URL

Encoding text with this tool takes only a second and happens entirely inside your browser. No upload, no sign-up, and no installation are required. The tool uses JavaScript's native encodeURIComponent() function. Follow these steps:

1. Paste your text. Type or paste any string into the input box — ASCII, Unicode, symbols, even multi-line text.
2. Click "Encode". The tool runs encodeURIComponent() on the input and writes the percent-encoded result into the output box in real time.
3. Copy the result. Click "Copy to Clipboard" to copy the encoded string, then paste it into your URL, API request or code.
4. Decode if needed. To reverse the operation, use the companion URL Decoder tool.

Because every step runs locally in your browser using JavaScript, your text is never uploaded to a server. This makes the encoding completely private, fast, and suitable for sensitive content such as tokens, keys and personal data.