URL Encoder / Decoder — Percent-Encode & Decode URIs

Fast, accurate URL encoding and decoding. Private by design—everything runs locally in your browser.

Input & Options

0 characters
Encoding mode   

Tips: Ctrl/Cmd + K focuses the input. Ctrl/Cmd + Enter repeats the last action. Alt + E encodes, Alt + D decodes.

Result

Understanding URL Encoding and Decoding

URL encoding (also known as Percent-encoding) is a mechanism for encoding information in a Uniform Resource Identifier (URI) under certain circumstances. It is used when a character that is not allowed in a URL (e.g., spaces, special symbols) needs to be part of the URL.

Why is URL Encoding Used?

  • Handling Special Characters: URLs can only contain a specific set of characters. Characters like spaces, `&`, `=`, `?`, `/`, `.` (when not part of a domain), etc., have special meanings in a URL structure. To include these characters literally, they must be encoded.
  • Preventing Malformed URLs: Encoding ensures that the URL is well-formed and can be correctly interpreted by web browsers and servers.
  • Data Integrity: When passing data as part of a URL (e.g., in query parameters), encoding ensures that the data is transmitted accurately without being misinterpreted.

How Encoding Works:

When a character is URL encoded, it is typically converted into a percent sign (`%`) followed by its two-digit hexadecimal representation. For example:

  • A space character (` `) becomes `%20`.
  • An ampersand (`&`) becomes `%26`.
  • A question mark (`?`) becomes `%3F`.

How This Tool Works

This URL Encoder/Decoder operates entirely client-side within your browser. No data is sent to a server, ensuring your privacy. It leverages JavaScript's built-in functions:

  • `encodeURIComponent()`: Used for encoding a URI component. This function escapes all characters except: A-Z a-z 0-9 - _ . ! ~ * ' ( ) . This is generally preferred for encoding individual URL parameters.
  • `decodeURIComponent()`: Used for decoding a URI component previously encoded by `encodeURIComponent()`.

For full URL encoding/decoding, the tool uses these functions to process the entire input, making it suitable for both full URLs and individual strings.

5 Fun Facts about URL Encoding

Space has two lives

Web forms turn spaces into +, but general URLs use %20. That’s why decoding form submissions needs a “+ → space” pass.

Form mode quirk

Reserved on purpose

encodeURI leaves characters like :/?#[]@ alone so a full URL keeps its shape; encodeURIComponent escapes almost everything to keep a single value safe.

Right tool, right spot

Emoji travel in disguise

When you paste an emoji in a path, it becomes UTF-8 bytes like %F0%9F%9A%80. In domains, the same rocket becomes xn-- punycode instead.

Unicode undercover

Double-encoding fingerprints

Seeing %2520 instead of %20? The %25 means the percent sign itself was encoded—usually a hint the string was encoded twice.

Decode once

Duplicates are valid

Query strings can repeat keys (?tag=js&tag=tools) and keep order. APIs often rely on that to represent arrays or priority lists.

Ordered pairs

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