Base64 Encoder & Decoder — Free Text & Image Converter Online
Encode and decode text or images to/from Base64. Supports URL-safe mode, image drag-and-drop, and overhead analysis — all in your browser, no server upload.
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Frequently Asked Questions
Q. What is Base64?
Base64 is an encoding scheme that represents binary data as ASCII characters. It is widely used in email attachments, JWT tokens, and data URIs.
Q. How does URL-Safe Base64 differ from regular Base64?
URL-Safe Base64 replaces + with - and / with _, allowing it to be used in URL parameters without percent-encoding.
Q. Does Base64 increase file size?
Yes — Base64 encoding increases size by approximately 33%. This tool shows the overhead percentage.
Q. Which image formats are supported?
JPEG, PNG, GIF, WebP, SVG, and any other format your browser supports.
Q. Can I convert Base64 back to an image?
Yes — in decode mode, paste Base64 image data (data:image/...;base64,...) to preview the image.
Q. Is my data sent to a server?
No — all processing happens locally in your browser.
How to Use
Choose Text mode or Image mode.
Type/paste text or drag and drop an image file.
Click Encode or Decode.
Copy the result or use the Swap button to flip input and output.
Expert Knowledge: Base64 Encoder & Decoder — Free Text & Image Converter Online
Base64 was introduced as part of the MIME (Multipurpose Internet Mail Extensions) standard in 1987. It uses 64 safe ASCII characters (A-Z, a-z, 0-9, +, /) to represent any binary data. Every 3 input bytes become 4 Base64 characters, causing the 33% size increase. Today it is ubiquitous in JWT (JSON Web Token), OAuth, HTML inline images (data URIs), and SSH keys.
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