Image to Base64 Converter Online Free
Convert any image to Base64 encoding instantly. Get the output as raw Base64, Data URI, an HTML img tag, a CSS background-image property, or Markdown — switch between them with one click. Includes a reverse converter to decode Base64 strings back to images. Everything runs in your browser; no image is uploaded anywhere.
100% private. Images are read using the FileReader API and never sent to any server.
How to Convert an Image to Base64 Free
- 01
Upload your image
Drop any image file onto the upload zone — JPG, PNG, WebP, GIF, SVG, or ICO. Max 5 MB.
- 02
Choose output format
Switch between tabs to get Raw Base64, Data URI, HTML img tag, CSS background-image, or Markdown format.
- 03
Copy or download
Copy the output string with one click, or download as a .txt file. Use the reverse converter to decode Base64 back to an image.
Frequently Asked Questions
What is a Base64 image?
A Base64 image is a binary image file encoded as a string of ASCII characters. This allows the image data to be embedded directly inside HTML, CSS, or JSON without referencing an external file. The data URI format (data:image/jpeg;base64,...) is the most common way to embed Base64 images in web pages.
When should I use Base64 images?
Base64 images are useful for small icons and logos that you want to inline in HTML or CSS to eliminate an extra HTTP request. They are also used in email templates (some email clients block external images), in React components as inline src values, and when passing image data through JSON APIs.
Why is my Base64 string larger than the original image?
Base64 encoding increases data size by approximately 33%. This is an inherent property of Base64 — every 3 bytes of binary data become 4 characters of text. For small images, this overhead is acceptable. For large images (over 50–100 KB), linking to the file is more efficient.
What is a Data URI?
A Data URI is a URL that contains the actual data inline rather than pointing to an external resource. It follows the format: data:[mediatype];base64,[data]. For example: data:image/png;base64,iVBORw... This can be used as the src attribute of an img tag or as a url() value in CSS.
How do I use a Base64 image in CSS?
Use the CSS tab to copy the background-image property. Paste it into your CSS rule: .element { background-image: url('data:image/png;base64,...'); }. You can also set background-size and background-repeat as needed.