What Is Base64 Encoding? A Beginner's Guide
You've seen strings like SGVsbG8gV29ybGQh and wondered what they are. That's Base64. Here's what it does and when to use it.
What Is Base64?
Base64 is a way to convert binary data (like images, or special characters) into plain ASCII text. It takes any data and represents it using only 64 "safe" characters: A-Z, a-z, 0-9, +, /, and = for padding.
How It Works
Input: "Hello World!"
Base64: "SGVsbG8gV29ybGQh"
Each character in the input is converted to its binary representation, then split into 6-bit chunks, each mapped to one of the 64 safe characters.
Common Uses
| Use Case | Example |
|----------|---------|
| Data URLs | Embedding small images directly in HTML/CSS: data:image/png;base64,... |
| API Authentication | HTTP Basic Auth: Authorization: Basic <base64-encoded-credentials> |
| Email attachments | MIME encoding for binary attachments |
| JSON Web Tokens | JWT payloads are Base64-encoded |
| URL-safe data | Passing binary data in query strings |
Is Base64 Encryption?
No. Base64 is encoding, not encryption. It's trivially reversible. Anyone can decode a Base64 string back to its original form. Never use Base64 to "protect" sensitive data like passwords.
Try It
Use our Base64 Encoder / Decoder:
- Paste text to encode → get Base64
- Paste Base64 to decode → get original text
- All processing happens in your browser
Size Increase
Base64 encoding makes data about 33% larger than the original binary. That's the trade-off: bigger size for text-safe transport.
Related Tools
- Base64 Encoder/Decoder — encode or decode instantly
- JSON Formatter — decode Base64 JWT payloads