Base64 Converter
Convert units with the Base64 Converter — enter a value and get accurate converted results instantly using verified formulas.
Formula
Base64: 3 bytes → 4 characters (33% size increase)
Base64 takes 3 bytes (24 bits) and divides them into 4 groups of 6 bits. Each 6-bit value (0-63) maps to a character from the 64-character alphabet. Padding with '=' is added when input length isn't divisible by 3.
Worked Examples
Example 1: Encode Credentials for API
Problem:Create Basic Auth header: username 'admin' and password 'secret123'.
Solution:Combine with colon: admin:secret123\n\nBase64 encode:\nInput: admin:secret123\nOutput: YWRtaW46c2VjcmV0MTIz\n\nHTTP Header:\nAuthorization: Basic YWRtaW46c2VjcmV0MTIz\n\nNote: This is encoding, NOT encryption. Use HTTPS for security!
Result:YWRtaW46c2VjcmV0MTIz
Example 2: Create Data URL for Small Image
Problem:Embed a tiny 1x1 transparent PNG directly in CSS.
Solution:1x1 transparent PNG Base64:\niVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=\n\nCSS usage:\n.element {\n background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=');\n}
Result:Data URL ready for CSS
Example 3: Decode Unknown Base64
Problem:Received Base64 string: SGVsbG8gV29ybGQh — what does it say?
Solution:Input (Base64): SGVsbG8gV29ybGQh\n\nClick 'Decode from Base64'\n\nOutput: Hello World!\n\nAnalysis:\n- 18 input characters\n- Decodes to 12 characters\n- Standard ASCII text\n- No padding needed (divisible by 4)
Result:Hello World!
Frequently Asked Questions
Why does Base64 make data larger?
Base64 increases size by approximately 33%. Every 3 bytes of input becomes 4 characters of output because you're representing 8-bit bytes with 6-bit characters. Additionally, padding ('=' characters) is added when input length isn't divisible by 3. A 1MB file becomes ~1.37MB when Base64 encoded.
When should I use Base64 encoding?
Use Base64 for: embedding images in HTML/CSS (data URLs), including binary data in JSON, sending attachments via email (MIME), storing binary in text-only databases, encoding credentials in HTTP Basic Auth, and transmitting data through text-only protocols. Don't use it for encryption—it's encoding, not security.
What is the difference between Base64 and encryption?
Base64 is encoding—it transforms data format but provides NO security. Anyone can decode Base64 instantly. Encryption scrambles data using a key, making it unreadable without the key. Never use Base64 to 'hide' sensitive data; use proper encryption (AES, RSA) for security. Base64 is for compatibility, not confidentiality.
What are Base64 URL-safe variants?
Standard Base64 uses + and / which have special meanings in URLs. URL-safe Base64 (Base64URL) replaces + with - and / with _ to avoid URL encoding issues. Some variants also omit padding (=). Use URL-safe Base64 for: query parameters, file names, JWT tokens, and anywhere URL encoding would cause problems.