URL Encoding Explained: When and Why to Encode URLs

Ever seen %20 in a URL and wondered what it means? That's URL encoding (also called percent-encoding), and getting it right is essential for web development.

What is URL Encoding?

URLs can only contain a limited set of characters. Spaces, special characters, and non-ASCII characters must be converted to a %XX format where XX is the hexadecimal value. For example, a space becomes %20, an ampersand becomes %26.

Why You Need It

• Query parameters - values containing &, =, or ? would break the URL structure
• Spaces in filenames - my file.pdf needs encoding for valid URLs
• International characters - non-ASCII letters and symbols must be encoded
• API requests - search queries, filter values, and user input in URLs need encoding

Reserved vs Unreserved Characters

Unreserved (safe as-is): letters, digits, -, _, ., ~

Reserved (have special meaning): : / ? # [ ] @ ! $ & ' ( ) * + , ; =

Reserved characters must be encoded when used as data (inside a query value), but kept as-is when used structurally (separating path segments).

Encode and Decode with Toolium

Use the URL Encoder/Decoder to encode text for safe inclusion in URLs, or decode percent-encoded strings back to readable text. Handles full Unicode including emoji and CJK characters.