What is Base64 Tool?
A Base64 Decoder is a fundamental utility for developers and IT professionals dealing with data encoding. Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It is commonly used to encode data that needs to be stored and transferred over media that are designed to deal with textual data, such as embedding images in HTML/CSS, sending email attachments, or transmitting complex data in URLs. This tool allows you to instantly decode Base64 strings back into their original text or binary format. Conversely, you can encode any text or file into a Base64 string. It handles various character sets (UTF-8, ASCII) correctly, ensuring that emojis and special characters are preserved. The processing is performed entirely in your browser, so your decoded data—which might be sensitive tokens, images, or documents—is never exposed to a server.
Input Formats
- Base64 strings
- Plain text
- Files (for encoding)
Output Results
- Decoded text
- Base64 string
- Downloadable files (images, pdfs)
Key Features
Who is this for?
Web Development
Decoding Base64 images (data:image/png;base64...) to view them or save them as files.
Security & Auth
Decoding JWTs (JSON Web Tokens) or Basic Auth headers to inspect the payload (Note: Base64 is encoding, not encryption).
Email Forensics
Decoding email attachments or headers that are encoded in Base64 within MIME messages.
How to Use
Paste your Base64 string into the input area.
The tool will automatically attempt to decode it.
Toggle between 'Text' and 'File' modes if necessary.
To Encode: Switch to 'Encode' tab and enter text or upload a file.
Copy the result or download the decoded file.
Examples
Input
SGVsbG8gV29ybGQhOutput
Hello World!Common Errors
- Invalid Base64 length (must be multiple of 4)
- Invalid characters (non-Base64 alphabet)
- Missing padding characters (=)
Code Examples
JavaScript
const encoded = btoa('Hello World'); // Encode
const decoded = atob(encoded); // DecodePython
import base64
encoded = base64.b64encode(b'Hello World')
decoded = base64.b64decode(encoded)