Base64 Encoder / Decoder

Encode or decode Base64 in one click — full Unicode support, instant results. No uploads, no servers. Paste your text and get results immediately.

 
 
 
  
 
Reference
  
What is Base64?
 
Base64 is a binary-to-text encoding scheme that represents binary data as printable ASCII characters using 64 symbols (A–Z, a–z, 0–9, +, /) plus = for padding. Every 3 input bytes become 4 output characters, expanding size by ~33%. Defined in RFC 4648.
 
Common uses
 
     
  • Email attachments — MIME encodes binary attachments as Base64 so they can travel through text-only email protocols.
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  • Data URLs — Embed images/fonts directly in HTML/CSS as data:image/png;base64,… without separate HTTP requests.
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  • API payloads — Pass binary data (images, PDFs, keys) through JSON or query strings that only accept text characters.
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Base64url and other variants
 
The standard Base64 alphabet uses + and /, which are special characters in URLs. Base64url (defined in RFC 4648 §5) replaces them with - and _ and often strips = padding. This variant is used in JWTs, URL query parameters, and filename-safe contexts. Other variants include MIME Base64 (line-wrapped at 76 characters for email) and the XML-safe alphabet.
 
Privacy
 
All encoding and decoding runs 100% in your browser. No data is ever sent to a server.
  
   
    
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