What is this tool?
Encode text strings and files into Base64 format or decode Base64 strings back to standard human-readable text and binary files directly in your browser tab.
When to use it?
Encode HTTP Basic Authentication header credentials, embed small image assets as Data URLs in HTML/CSS, decode Base64 payload data from webhooks, or format binary data for text-only communication channels.
How does it work?
Converts UTF-8 text strings into byte arrays using TextEncoder/TextDecoder before executing window.btoa and window.atob conversions, properly handling multi-byte Unicode characters without Latin1 truncation.
Technical Specifications & Standards
Base64 represents 6 bits of data per character using an alphabet of 64 ASCII characters (A-Z, a-z, 0-9, +, /) and "=" for padding. Encoding increases data size by approximately 33%.
Operating Limits & Considerations
- Base64 encoding increases payload size by ~33%. It should not be used for large media files where binary transfer is supported.
- Base64 is an encoding scheme, not encryption. It provides zero confidentiality or security on its own.
Example Conversions
Input Text: "Hello, World!"
Base64 Encoded: "SGVsbG8sIFdvcmxkIQ=="
Standards & Technical References
Frequently Asked Questions
No. Base64 is a data representation format, not an encryption method. Anyone can immediately decode a Base64 string without a password or key.
Standard Base64 uses "+" and "/" characters, which have special meanings in URLs and filenames. Base64URL replaces "+" with "-" and "/" with "_", and typically omits trailing "=" padding characters.