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Convert Images to Base64 Data URIs Convert images to Base64-encoded data URIs for embedding in HTML and CSS.

Base64 Image Encoder illustration
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Base64 Image Encoder

Convert images to Base64-encoded data URIs for embedding in HTML and CSS.

1

Upload Image

Select or drag and drop an image file (PNG, JPG, GIF, SVG, WebP).

2

View Base64 Output

The Base64 data URI is generated instantly.

3

Copy Data URI

Click Copy to copy the full data URI for use in HTML or CSS.

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What Is Base64 Image Encoder?

A Base64 Image Encoder converts image files into Base64-encoded data URIs that can be embedded directly in HTML, CSS, or JavaScript. Instead of referencing an external file, the image data is inline as a data:image/type;base64,... string. This eliminates extra HTTP requests and is ideal for small icons, logos, and sprites. The tool reads the image using the FileReader API, detects the MIME type automatically, and produces a complete data URI. Supports PNG, JPEG, GIF, SVG, WebP, and other common formats. All processing happens in your browser — images never leave your device.

Why Use Base64 Image Encoder?

  • Eliminate extra HTTP requests by inlining small images
  • Automatic MIME type detection for all common image formats
  • 100% client-side — images never leave your browser
  • Generates ready-to-use data URIs for HTML and CSS

Common Use Cases

HTML Embedding

Embed small icons and logos directly in HTML img src attributes.

CSS Backgrounds

Use data URIs in CSS background-image properties.

Email Templates

Inline images in HTML emails to avoid blocked external resources.

Single-File Apps

Bundle images directly into JavaScript for offline-capable applications.

Technical Guide

The FileReader API reads the selected image as an ArrayBuffer, then converts it to a Base64 string via readAsDataURL(). The resulting data URI follows the format data:[MIME];base64,[encoded-data]. MIME type is auto-detected from the file. Base64 encoding increases data size by approximately 33%, so this technique is most efficient for images under 10KB. For larger images, external file references with proper caching are more performant.

Tips & Best Practices

  • 1
    Best for small images under 10KB to avoid bloating HTML/CSS file size
  • 2
    Use for icons, logos, and UI sprites that need to load instantly
  • 3
    Data URIs are not cached separately — they're part of the HTML/CSS file
  • 4
    SVG images can also be URL-encoded instead of Base64 for smaller size

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Frequently Asked Questions

Q Is this tool free?
Yes, completely free with no signup required.
Q Are my images uploaded to a server?
No. All processing happens in your browser — images never leave your device.
Q What image formats are supported?
PNG, JPEG, GIF, WebP, SVG, ICO, BMP, and any format your browser supports.
Q Is there a file size limit?
No hard limit, but Base64 adds 33% overhead — best for small images.
Q Can I use the output in CSS?
Yes, paste the data URI in url() for background-image or any CSS image property.

About This Tool

Base64 Image Encoder is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.