What is URL encoding (percent-encoding)?

URL encoding converts characters that are not allowed in URLs into a safe representation. Each unsafe character is replaced with a percent sign (%) followed by its two-digit hexadecimal ASCII code. For example, a space becomes %20, and an ampersand becomes %26. This allows any text — including special characters, Unicode, and binary data — to be safely embedded in a URL.

Why do spaces become %20 in URLs?

Spaces are not valid URL characters because they are used as delimiters in HTTP requests. %20 is the percent-encoded form of a space (ASCII value 32, hex 20). Some web forms encode spaces as + instead of %20 in query strings (application/x-www-form-urlencoded format), but %20 is the universally correct encoding per RFC 3986.

What is the difference between encodeURI and encodeURIComponent?

In JavaScript, encodeURI() encodes a complete URL — it leaves URL-structural characters like /, ?, &, = and # intact because they have meaning in URLs. encodeURIComponent() encodes a URL component (like a query parameter value) — it encodes those structural characters too, because inside a parameter value they must not be interpreted as URL structure. Use encodeURIComponent when encoding individual query string values; use encodeURI only for full URLs.

When should I decode a URL?

Decode URLs when you receive a URL-encoded string and need to read or display the original text: processing form submissions, reading URL parameters in server code, debugging API requests, or converting encoded URLs into readable links. The decoder above handles both %XX encoding and + signs for spaces.

Encoding & Conversion

URL Encode / Decode

Encode or decode URL components (percent-encoding) — runs entirely in your browser.

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Output

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URL encoding — frequently asked questions

Base64 Encode / Decode

Encode text to Base64 or decode Base64 to text with full UTF-8 support.

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HTML Entity Encoder

Encode and decode HTML entities — named and numeric references.

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Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes in your browser.

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