Base64 Encoder & Decoder
Convert text, files, or images to Base64 instantly — or decode Base64 data back into its original format. All processing happens directly in your browser for maximum speed and privacy.
What is Base64?
Base64 is a binary-to-text encoding scheme that converts raw binary data into a text format consisting of 64 safe ASCII characters. It is commonly used when binary data needs to be transmitted through systems designed to handle text.
For example, Base64 encoding is widely used in:
- Email attachments (MIME encoding)
- Embedding images in HTML and CSS using Data URLs
- Authentication headers in APIs
- JWT tokens and security payloads
- Transporting binary data inside JSON
Common Developer Use Cases
Developers frequently encounter Base64 when debugging APIs or working with encoded data streams. This tool makes it easy to quickly inspect or generate Base64 data.
- Convert files into Base64 for API requests
- Decode Base64 responses from web services
- Preview Base64 encoded images
- Create data URLs for inline assets
- Inspect encoded JWT payloads
Why Use an Online Base64 Tool?
Using a browser-based encoder allows you to instantly convert data without installing software or running command-line tools. Because all processing occurs locally inside your browser, your data never leaves your device.
Frequently Asked Questions
What can this tool encode and decode?
This tool supports plain text (UTF-8), JSON, CSV, images (PNG, JPG, GIF), PDFs, and other binary files. You can paste content directly or drag and drop files to convert them instantly.
Is my data secure?
Yes. All encoding and decoding happens entirely in your browser. Your files and text are never uploaded to any server, ensuring maximum privacy.
How does drag and drop work?
Simply drag a file into the drop zone. Text files will display their contents in the input field, while images and other files will show the filename and generate Base64 output. Images will also display a preview automatically.
Why does decoded output sometimes look unreadable?
If you decode a binary file such as an image or PDF, the result will appear as unreadable characters. This is expected because binary data is not human-readable. Use the “Download Decoded File” button to save it properly.
How does the “Download Decoded File” button work?
The tool detects whether your data is Base64 and converts it back into its original binary format. It also attempts to identify the correct file type (such as PNG, JPG, or PDF) before downloading. If the content is plain text, it will download as a .txt file.
Can I encode large files?
Yes. This tool uses chunked processing (streaming) to handle large files efficiently without freezing your browser. Extremely large files may still be limited by your browser’s memory.
What is Auto mode?
Auto mode automatically detects whether your input is Base64 or plain text. If Base64 is detected, it will decode it. Otherwise, it will encode the input. You can manually switch modes at any time.
Why isn’t my Base64 decoding working?
This usually happens if the Base64 string is incomplete, contains invalid characters, or includes extra spaces or line breaks. Try cleaning the input or switching modes manually.
Can I use Base64 images in HTML or CSS?
Yes. You can embed Base64 images directly into HTML or CSS using data URLs. For example: <img src="data:image/png;base64,..." /> or in CSS using background-image.
Does this support Unicode text?
Yes. The tool correctly handles UTF-8 encoding, so emojis and non-English characters are preserved.
Why is Base64 output larger than the original?
Base64 encoding increases the size of data by approximately 33%. This is a normal trade-off for converting binary data into a text-safe format.
When should I use Base64?
Base64 is commonly used for embedding images in HTML/CSS, sending binary data through APIs, encoding tokens like JWTs, and storing small assets inline.