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Base64 encoder / decoder

Encode Unicode text as Base64 or decode it, with URL-safe options and an interactive byte preview.

0 / 100,000 characters

Base64

Your conversion appears here as you type.
0 output characters
Inspect UTF-8 bytes

0 bytes · each block below is one byte in hexadecimal.

Processed on your device

How it works & useful details

How to use this tool

Choose Encode or Decode, paste text, and inspect the live conversion. Swap reverses the result into the input.

Details and limits

UTF-8 text only. Invalid UTF-8 and noncanonical Base64 padding bits are rejected. Standard Base64 uses + and /; URL-safe uses - and _ and omits padding. Both accept correctly unpadded input and ASCII whitespace.

Up to 100,000 input code units. Live preview pauses above 8,000. Inputs and outputs stay on your device.