Base64 Encoder / Decoder
Instantly encode plain text to Base64 or decode Base64 strings back to readable text. Supports standard and URL-safe modes.
Input
Output
About Base64
- Base64 encoding converts binary or text data into an ASCII string, making it safe to transmit over text-based protocols.
- URL-safe mode replaces '+' with '-' and '/' with '_', suitable for use in URLs and filenames.
- Common uses: embedding images in HTML/CSS, encoding email attachments (MIME), storing binary data in JSON.
- How it works: every 3 bytes of input are mapped to 4 ASCII characters from the set A–Z, a–z, 0–9, +, /. This encoding increases the output size by approximately 33%.
- Padding: one or two '=' characters may appear at the end to make the output length a multiple of 4. Many decoders accept unpadded input — this tool handles both automatically.
- Base64 is NOT encryption. It is trivially reversible and provides zero security. Never use it to hide or protect sensitive data such as passwords or tokens.
- Avoid Base64 for large files (images, videos, archives): the ~33% size overhead and encode/decode cost make direct binary transfer far more efficient for files over a few KB.
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