Base64 Encoder & Decoder
Encode text or files to Base64, or decode Base64 strings back to plain text. All processing happens in your browser with full UTF-8 support.
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Frequently Asked Questions
What is Base64 encoding?
Base64 is a binary-to-text encoding scheme that represents binary data as an ASCII string. It uses 64 printable characters (A-Z, a-z, 0-9, +, /) to encode data, making it safe to transmit over text-based protocols like email or embed in JSON and XML.
Why is my Base64 output larger than the input?
Base64 encoding increases data size by approximately 33%. Every 3 bytes of input become 4 Base64 characters. This overhead is the trade-off for being able to safely represent binary data as text.
Does this tool support file encoding?
Yes. Click the “Upload File” button to select any file from your computer. The file will be read and converted to its Base64 representation entirely in your browser. No data is uploaded to any server.
How does this tool handle UTF-8 characters?
This tool properly encodes and decodes multi-byte UTF-8 characters (including emojis, accented letters, and CJK characters) by using the TextEncoder and TextDecoder APIs rather than the legacy btoa/atob approach alone.