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Base64 Decode

Free online Base64 decoder. Convert Base64 encoded strings back to plain text instantly. Handles standard and URL-safe Base64. All processing in your browser.

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Base64 Input
0 chars
Text Output
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Frequently asked questions

4 answers
Base64 decoding reverses the encoding process: it takes a string of Base64 characters (A-Z, a-z, 0-9, +, /) and converts them back to the original binary data or text. Every 4 Base64 characters map back to 3 bytes of original data. The decoder interprets those bytes as UTF-8 text to produce the human-readable output.

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About Base64 Decoding

Base64 decoding is the inverse of encoding: it converts a Base64 string back into the original binary data or human-readable text. The process reads 4 Base64 characters at a time, extracts the 24 bits they represent, and writes 3 bytes of output. This decoder handles both standard Base64 (RFC 4648 Section 4) and URL-safe Base64 (RFC 4648 Section 5) automatically, accepting either + and / or - and _ as the special characters. It also handles inputs with missing padding, which is common in JWT tokens and certain API responses.