123noteBase64 Encode & Decode
Convert text, images and files directly in your browser.
How to use
Convert UTF-8 text, image files and other files in your browser without signing in. Choose Encode or Decode, select Standard Base64 or Base64URL, then run the conversion. Strict decoding rejects malformed input; compatible mode shows formatting changes for your approval.
Text conversions can be saved to your Google account only when you sign in and press Save conversion. The text input and format options are sent over HTTPS and stored encrypted. Files, images and Data URLs are never saved to your account. Saved text can be reopened or deleted.
The local conversion limit is 5 MiB. Binary decoded output can be downloaded as bytes. Base64 is an encoding, not encryption. The app shell can work offline after it has been cached; account storage needs a connection.
Frequently asked questions
Is my input uploaded?
Conversion stays in your browser. Only a text conversion that you explicitly save while signed in is sent to encrypted account storage.
Can I save images or files?
No. File bytes, images and Data URLs stay on your device. Account storage accepts UTF-8 text conversions only.
What is the difference between Base64 and Base64URL?
Standard Base64 uses + and /. Base64URL uses - and _. Padding is a separate choice.