URL Encoder / Decoder — Tutorial

What is URL encoding?

URL encoding (also called percent-encoding) converts special characters in text to a format safe for URLs, using percent-encoding (e.g., space becomes %20). Decoding reverses this process.

Why URL encoding is needed

URLs can only contain certain ASCII characters. Special characters, spaces, and non-ASCII characters must be encoded to be transmitted safely in URLs.

Common encodings

• Space: %20 (or + in form data)
• Ampersand: & → %26
• Question mark: ? → %3F
• Hash: # → %23
• Slash: / → %2F
• Plus: + → %2B

Examples

Original: Hello World!
Encoded: Hello%20World%21

Original: user@example.com
Encoded: user%40example.com

Official documentation

• RFC 3986 - URI Generic Syntax
• MDN: encodeURIComponent()
• W3C: Internationalized Domain Names and IRIs

How to use the tool

1. Paste or drop text/URL, or load from a file.
2. Click Encode or Decode to process the input.
3. Copy or download the result.
4. History: Last 5 actions are stored locally. Use Clear history to remove them.

Open the tool: URL Encoder / Decoder

Privacy & limits

• All encoding/decoding is performed locally in your browser; no data is uploaded.
• Max file size: 2 KB.

Troubleshooting

• Encoding errors: Some characters may not encode if input contains invalid UTF-8 sequences.
• Double encoding: Be careful not to encode already-encoded text (e.g., %20 becoming %2520).
• Form data vs. URI components: This tool uses URI component encoding. Form data may use + for spaces instead of %20.
• International characters: Non-ASCII characters are encoded as UTF-8 bytes then percent-encoded.
• Large files: Browsers may slow down for very large files. Prefer download for big outputs.

When to use URL encoding

• Query parameters: Always encode values in URL query strings
• Form submissions: When submitting forms via GET requests
• API requests: When passing data in URL paths or parameters
• File names: When creating URLs with file names containing special characters