Image to Base64

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data (such as images) as a string of ASCII characters. It works by dividing the binary data into groups of 3 bytes (24 bits) and converting each group into 4 ASCII characters from a set of 64 characters (A-Z, a-z, 0-9, +, and /). This encoding increases the data size by approximately 33%, but the result is a plain text string that can be embedded in HTML, CSS, JSON, and other text-based formats.

Base64 encoding is commonly used to embed small images directly into web pages or CSS files, eliminating the need for separate HTTP requests. This can improve page load performance for small icons and UI elements by reducing the number of network round trips. However, for larger images, Base64 encoding actually increases the total payload size and can hurt performance because the encoded data cannot be compressed as effectively as binary image data.

This tool converts images to Base64 entirely in your browser. No files are uploaded to any server, making it safe to use with sensitive or proprietary images.

Data URI vs Raw Base64

This tool offers two output formats. A Data URI (or data URL) includes a prefix that tells the browser the MIME type of the encoded content, such as data:image/png;base64,iVBORw0KG.... This format can be used directly in HTML attributes like src on an <img> tag or in CSS url() functions without any additional processing.

Raw Base64 is just the encoded string without any prefix. This format is useful when you are building the data URI yourself, storing the encoded data in a database or JSON field, or passing it to an API that expects plain Base64. You will need to add the appropriate prefix manually when using raw Base64 in HTML or CSS.

How to Use This Tool

Drag and drop an image onto the drop zone, or click the drop zone to open a file picker. The tool will read the file using the browser's FileReader API, generate a Base64 string, and display both a preview of the image and the encoded output. You can switch between Data URI and Raw Base64 output formats using the toggle buttons, then copy the result to your clipboard.

The tool displays the file name, MIME type, original file size, and the size of the Base64 output to help you assess whether embedding the image is practical for your use case. A 2MB size warning helps you avoid encoding very large images, which can cause browser performance issues and produce excessively long Base64 strings.

Frequently Asked Questions

Is my image uploaded to a server?

No. All processing happens entirely in your browser using the FileReader API. Your image never leaves your device. No files are uploaded, stored, or transmitted to any server. This makes it safe to use with confidential or proprietary images.

Why is the Base64 output larger than the original file?

Base64 encoding increases data size by approximately 33% because every 3 bytes of binary data are represented as 4 ASCII characters. Additionally, the Data URI format includes a MIME type prefix. For a 100KB image, expect the Base64 output to be around 133KB.

When should I use Base64 images instead of image files?

Base64 images are best for small, frequently used assets like icons, logos, and UI elements where reducing HTTP requests improves performance. For larger images (over 10KB), using separate image files with proper caching headers is generally more efficient because binary images compress better with gzip and can be cached independently.

What image formats are supported?

The tool supports all image formats that your browser can read, including PNG, JPEG, GIF, WebP, SVG, BMP, ICO, and AVIF. The resulting Base64 string preserves the original format and can be decoded back to the exact same image.

Why is there a 2MB size warning?

Large images produce very long Base64 strings that can consume significant memory and slow down your browser. A 2MB image produces roughly 2.7MB of Base64 text, which can make the output textarea sluggish. The warning is advisory; you can still encode larger images, but be aware of potential performance impacts.

Can I use the output in CSS?

Yes. Select the Data URI format, copy the output, and use it in your CSS like this: background-image: url("data:image/png;base64,...");. This technique is called CSS inlining and is commonly used for small background images and icons.