Base64 vs URL Encoding: When to Use Which (Clear Guide)
Published April 2025 · 5 min read
Base64 and URL encoding solve different problems. Here's when to use each.
URL Encoding (Percent Encoding)
Replaces unsafe URL characters with %XX. Used for query parameters and form data.
Input: hello world&foo=bar
Output: hello%20world%26foo%3DbarTry it: URL Encoder/Decoder
Base64 Encoding
Converts binary data to ASCII text using A-Z, a-z, 0-9, +, /. Used for embedding binary data in text formats.
Input: Hello World
Output: SGVsbG8gV29ybGQ=Try it: Base64 Encoder/Decoder
When to Use URL Encoding
- Query string parameters:
?name=John%20Doe - Form submissions (application/x-www-form-urlencoded)
- Any data going into a URL
When to Use Base64
- Embedding images in HTML/CSS:
data:image/png;base64,... - Email attachments (MIME)
- Storing binary data in JSON
- Basic HTTP authentication headers
Key Differences
| Feature | URL Encoding | Base64 |
|---|---|---|
| Purpose | Safe URLs | Binary→Text |
| Size increase | ~3x for special chars | ~33% always |
| Reversible | Yes | Yes |
| Output chars | %XX hex | A-Za-z0-9+/= |