Base64 Decoder
Decode Base64 encoded strings back into readable plain text and UTF-8 strings.
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About the Base64 Decoder
When debugging JWT authorization headers, inspecting webhook payloads, or parsing email attachments, decoding Base64 back into its original text is essential.
How to Use the Base64 Decoder
- 1Paste your Base64 encoded string into the input area.
- 2Click "Decode to Plain Text".
- 3Instantly view the decoded text.
- 4Copy the result to your clipboard or download it as a text file.
How It Works & Underlying Logic
The decoder reverses the Base64 table mapping: each 4-character block is converted into three 8-bit bytes, and the resulting byte stream is decoded as a standard UTF-8 string.
Decoded Bytes = Base64CharIndices[4] mapped to 3 Bytes (24 bits) -> UTF8 StringPractical Calculation Examples
Base64 Decoded to Text
Decoding sample string
Helpful Tips & Best Practices
- •Ensure the input Base64 string length is a multiple of 4 (with standard = padding if applicable).
- •If your Base64 string contains dashes (-) or underscores (_), it is URL-Safe Base64.
Base64 Decoder FAQ
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