Base64 Encoder Decoder
Base64 Encoder Decoder is a free developer tool that runs directly in your browser with no account required.
About this tool
Convert text to Base64 and back without leaving the page. The tool handles Unicode correctly by transcoding input to UTF-8 bytes before encoding, so emoji, accented characters, and non-Latin scripts round-trip cleanly.
How to use
- Enter your string in the Text field.
- Set Mode to Encode to produce Base64, or Decode to convert Base64 back to text.
- Copy the result from the output box.
Frequently asked questions
Does it handle Unicode and emoji?
Yes. Input is converted to UTF-8 bytes (via the encodeURIComponent technique) before Base64 encoding, and decoded output is interpreted as UTF-8, so multibyte characters survive the round trip.
Can I encode binary files?
No, this tool works on text you paste into the field. For images or other binary files you would need a file-based encoder.
What happens if I decode an invalid string?
You get a clear "Input is not valid Base64" error instead of garbled output. Check for stray characters, missing padding, or accidental line breaks.
Is URL-safe Base64 supported?
The encoder produces standard Base64 with + and / characters. To decode URL-safe Base64, replace - with + and _ with / first.
Is my text sent to a server?
No. Encoding and decoding use the browser's built-in atob and btoa functions, so everything stays on your device.