URL Encoder/Decoder

Encode and decode URL strings instantly.

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Text will be URL encoded (percent encoding)

What is URL Encoding?

URL encoding, also known as percent encoding, is a mechanism for encoding information in a Uniform Resource Identifier (URI). It ensures that special characters and non-ASCII characters can be safely transmitted in URLs without breaking the URL structure or causing parsing errors.

The encoding uses a percent sign (%) followed by two hexadecimal digits. For example, a space character becomes %20, and the @ symbol becomes %40. This format is defined in RFC 3986, the standard for URI syntax.

RFC 3986 specifies which characters are 'reserved' (have special meaning in URLs) and which are 'unreserved' (safe to use without encoding). Reserved characters must be encoded when used in parts of a URL where they have special meaning.

When to Use URL Encoding

URL encoding is essential in several scenarios:

Query parameters: Values in URL query strings (after ?) must be encoded to handle spaces, special characters, and non-ASCII text
Path segments: When URLs contain user-generated content or file names with special characters
Special characters: Characters like &, =, ?, #, and spaces have special meaning in URLs and must be encoded
International characters: Non-ASCII characters like é, ñ, or Chinese characters must be encoded using UTF-8 percent encoding
HTML forms: Form data submitted via GET method is automatically URL encoded in the query string

URL Encoding Rules

Understanding which characters need encoding helps you create valid URLs:

A-Z, a-z, 0-9Never encoded - safe to use as-is

- _ . ~Never encoded - these characters are safe in URLs

! * ' ( ) ; : @ & = + $ , / ? # [ ]Must be encoded when used in contexts where they have special meaning

SpaceAlways encoded as %20 (or + in query strings)

%Encoded as %25 - the percent sign itself must be encoded

Common Encoding Examples

Here are real-world examples of URL encoding:

Original:

Hello World

Encoded:

Hello%20World

Original:

café & restaurant

Encoded:

caf%C3%A9%20%26%20restaurant

Original:

price=$100

Encoded:

price%3D%24100

Common URL Encoding Mistakes

Avoid these frequent errors when working with URL encoding:

Double encoding: Encoding an already-encoded string results in %2520 instead of %20. Always check if a string is already encoded before encoding again.
Encoding entire URLs: Only encode the parts that need encoding (query values, path segments), not the entire URL including protocol and domain.
Encoding forward slashes: Forward slashes (/) in paths should NOT be encoded. Only encode them in query parameter values.
Encoding query parameters only: Remember that path segments with special characters also need encoding, not just query strings.
Case sensitivity: Percent encoding uses uppercase hexadecimal (A-F), though lowercase (a-f) is also valid. Be consistent in your encoding.

encodeURIComponent vs encodeURI

JavaScript provides two encoding functions with different purposes:

encodeURIComponent()

Encodes almost everything, including reserved characters. Use this for encoding query parameter values, form data, or any string that will be part of a URL component.

encodeURI()

Encodes the URI but preserves characters that have meaning in URIs (like :, /, ?, #). Use this when encoding an entire URI that you want to keep functional.

Rule of thumb: Use encodeURIComponent() for values that go INTO a URL (query parameters, path segments). Use encodeURI() only when encoding an entire URL that you want to remain usable.

URL Encoder/Decoder

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