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🔑 Base64 Encoder & Decoder

Pick a mode and choose up to 10 characters to encode plain text into Base64, or decode Base64 characters back into text.

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What this calculator does

Base64 is a way of representing binary or text data using only 64 safe, printable characters (A-Z, a-z, 0-9, +, and /). It’s widely used for embedding data in text formats like URLs, email, and JSON.

How the calculation works

Select a mode, then pick each character of your short input one at a time from the dropdowns. To encode, the tool groups your text’s character codes into 3-byte chunks and maps each 6 bits to one of the 64 Base64 characters, padding with ‘=’ as needed, exactly per the standard RFC 4648 algorithm. To decode, it reverses the process, turning groups of 4 Base64 characters back into the original bytes.

This character-by-character input is meant for short demonstrations of how Base64 works; for encoding or decoding long text, a dedicated text-based tool is more practical.

Last reviewed August 2026