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📄 Base64 Encoder/Decoder

Encode and decode Base64 strings with support for standard and URL-safe variants.

All processing happens locally in your browser. No data is sent to any server. GDPR/DORA compliant.
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File to Base64

Convert files to Base64 encoded strings. Maximum file size: 5MB.

Drag & drop a file here or click to select

Supported: Any file type up to 5MB

Base64 Reference

Standard Base64

  • Uses: A-Z, a-z, 0-9, +, /
  • Padding: = (equals sign)
  • RFC 4648 compliant
  • Common in email (MIME)

URL-Safe Base64

  • Uses: A-Z, a-z, 0-9, -, _
  • No padding or optional
  • Safe for URLs and filenames
  • Used in JWTs

Size Calculation

  • Encoded size = ceil(n/3) * 4
  • ~33% larger than original
  • Every 3 bytes = 4 chars
  • Padding fills to 4 chars

Common Uses

  • Data URLs in HTML/CSS
  • Email attachments (MIME)
  • API payload encoding
  • Configuration files