Base64 Encoder / Decoder

Encode text or files to Base64 and decode Base64 strings back to plain text. Supports Unicode.

Plain Text
Base64 Output 

        

      

      

        
        
      

    


    
  

  



Related Tools

  

    URL EncoderEncode URLs
    Image to Base64Convert images
    HTML EntitiesEncode HTML chars
  










  
About the Base64 Encoder / Decoder

  

    The Base64 Encoder / Decoder converts plain text or binary data into Base64 format and back, entirely in your browser with no data sent to any server. It is an essential tool for developers working with APIs, email attachments, data URIs, and authentication tokens. Full Unicode support ensures that non-ASCII characters such as accented letters, emoji, and CJK scripts are handled correctly.
  

  
Common use cases

  




  
Frequently Asked Questions

  


    

      How does Base64 encoding actually work?
      
Base64 encoding works by taking every three bytes of binary input (24 bits) and splitting them into four groups of six bits each, then mapping each 6-bit value to one of 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). If the input length is not a multiple of three, padding characters (=) are appended to make the output length a multiple of four. This ensures binary or non-ASCII data can be safely transmitted through text-only channels such as email or JSON payloads.

    


    

      Is my data safe when using this Base64 tool?
      
Yes  -  all encoding and decoding happens entirely within your browser using JavaScript's built-in btoa and atob functions combined with URI encoding for full Unicode support. No data is ever sent to a server, stored in a database, or logged in any way. You can verify this by using your browser's network inspector tab, which will show zero outbound requests when you encode or decode.

    


    

      Does Base64 encoding work with Unicode and emoji characters?
      
Yes. This tool uses a encodeURIComponent + unescape technique before calling btoa, which correctly handles the full Unicode range including multi-byte characters, accented letters, CJK ideographs, and emoji. Decoding reverses the process using decodeURIComponent after atob, so round-trip fidelity is guaranteed for any text your browser can represent.

    


    

      What are the limitations of this Base64 encoder?
      
This tool is optimised for text input; for large binary files such as images or archives, use the dedicated Image to Base64 tool instead. Very large inputs (several megabytes of text) may cause the browser tab to become temporarily unresponsive because JavaScript is single-threaded. Additionally, Base64-encoded output is approximately 33% larger than the original input due to the 6-bit to 8-bit character mapping overhead.

    


    

      How does this compare to other Base64 tools or command-line utilities?
      
Command-line tools like base64 on Linux/macOS or PowerShell's Convert.ToBase64String require terminal access and may not handle Unicode consistently across operating systems. This browser-based tool requires no installation, works on any modern browser including Chrome, Firefox, Safari, and Edge, and provides the same RFC 4648-compliant Base64 output with correct Unicode handling on every platform.