Base64 Encoder/Decoder
Encode and decode text and files to/from Base64 format. Perfect for data encoding, email attachments, and web development applications.
How to Use the Base64 Converter
- Choose Direction: Select encode (text to Base64) or decode (Base64 to text)
- Enter Data: Paste your text or Base64 string in the input field
- Convert: Click the encode or decode button to process your data
- Copy Result: Use the copy button to save the converted output
- File Support: Some converters support direct file encoding and decoding
What is Base64 Encoding?
The Basics
Base64 converts binary data into text using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). This encoding makes binary data safe for transmission through systems that only handle text. The output is roughly 33% larger than the input due to the encoding overhead.
Why Use Base64?
Many systems were designed for text, not binary data. Email protocols, JSON, XML, and URLs can't handle raw binary files directly. Base64 bridges this gap by representing binary content as text. It ensures data survives transport through systems that might otherwise corrupt binary formats.
Not Encryption
Base64 is encoding, not encryption or security. Anyone can decode Base64 instantly. Don't use it to hide sensitive information. It's designed for compatibility and data integrity during transmission, not confidentiality. Always use proper encryption (like AES) for security.
Common Base64 Use Cases
Web Development
- Embedding small images directly in HTML or CSS (data URLs)
- Sending binary files through JSON APIs
- Storing binary data in text-only databases
- Encoding file attachments in web forms
Data Transmission
- Email attachments (MIME encoding)
- Sending credentials in HTTP authentication headers
- Embedding certificates and keys in configuration files
- Passing binary data through URL parameters
Example: Data URL
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA...
This embeds an image directly in HTML without a separate file request.
Technical Details
How Encoding Works
Base64 groups input bytes into sets of three (24 bits), then divides into four 6-bit groups. Each 6-bit group maps to one of 64 characters. Padding characters (=) fill out the final group if needed.
Binary: 01001000 01101001
Base64: SGk=
Character Set
A-Z (26 chars)
a-z (26 chars)
0-9 (10 chars)
+ and / (2 chars)
= for padding
URL-safe variant:
Replaces + with - and / with _
Frequently Asked Questions
Is Base64 secure for sensitive data?
No. Base64 is easily reversible and provides zero security. It's encoding, not encryption. Anyone can decode Base64 instantly. Use proper encryption algorithms like AES for security. Base64 is only for compatibility and data integrity.
Why does Base64 make data larger?
Base64 uses 6 bits per character but requires 8 bits to store each character. This creates about 33% overhead. Three input bytes (24 bits) become four Base64 characters (32 bits). The trade-off is compatibility with text-only systems.
When should I use URL-safe Base64?
Use URL-safe Base64 when encoding data for URLs or file names. Standard Base64 uses + and / which have special meanings in URLs. URL-safe Base64 replaces these with - and _ which are safe in URLs without percent-encoding.
Can I encode any file type to Base64?
Yes. Base64 works with any binary data - images, videos, documents, executables, etc. However, large files create very long Base64 strings. For files over a few hundred kilobytes, direct binary transmission is more efficient than Base64.
What does the = padding mean?
The = characters pad the output to a multiple of four characters. They indicate that the final group had fewer than three input bytes. Padding helps decoders determine the exact input length. Some implementations omit padding when context makes it unnecessary.