Base64 Decode Online

Base64 decoding is the process of converting Base64-encoded ASCII text back to its original binary or text form. Base64 encoding represents binary data using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). Decoding reverses this process, restoring the original data. It is commonly used to retrieve text, images, or files that were encoded for safe transmission over email, URLs, or APIs.

The tool automatically detects invalid Base64 input and shows a clear error message. Common causes of invalid Base64 include missing padding characters (=), illegal characters that are not part of the Base64 alphabet, or incorrect string length. The error message will help you identify and fix the issue so you can retry the decoding.

Yes. You can upload a text file containing Base64-encoded data by clicking the upload button or by dragging and dropping the file directly onto the input area. The tool will read the file contents and decode the Base64 data automatically. This is especially useful for large Base64 strings that are inconvenient to copy and paste manually.