Convert Base64 encoded strings back to plain text

Decode standard Base64 into the original bytes or text.

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ToolBase64 Decode
Input
Output
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Preview

How it works

Four Base64 characters represent 24 bits as four 6-bit values; decoding recombines them into up to three bytes and handles = padding in the final group. The standard alphabet uses plus and slash.

  • Padding makes final length explicit.
  • Unpadded input can be accepted when length is known.

Worked example

Simple Text
Decode a Base64 string back to plain text
Input
											SGVsbG8sIFdvcmxkIQ==
Output
												Hello, World!

When to use this

Basic Auth, MIME attachments, and data URLs decode Base64.

Edge cases

  • URL-safe - and _ need an alphabet switch.
  • Bad padding can leave an incomplete final group.
  • Decoded bytes are not guaranteed UTF-8 text.

References