BrowserTools

Image to Base64

Data-URI encoder with CSS/HTML snippets

By Guga — BrowserTools maintainer, Tbilisi, Georgia Updated 2026-09-21
Free Private No uploads
What is Image to Base64?

Base64 is how you put binary inside text. An image becomes a data URI you can paste straight into an HTML attribute, a CSS rule, a JSON document, or an email template with no separate file to host. The catch is arithmetic: base64 encodes three bytes as four characters, so the payload is about a third larger than the original, and browsers will not cache it the way they cache a real file. This tool shows you the encoded length next to the original file size as a percentage so you can see the cost before you commit. Files above 8 MB are declined with an explanation rather than freezing the tab. It handles images of any type the browser can read, and it never converts the format — the data URI keeps whatever the source was.

Convert images to Base64 data URIs ready to embed in HTML, CSS or JSON — with ready-made <img> and background-image snippets generated for you. Essential for single-file apps and emails.

Private Image to Base64 In Your Browser

Image to Base64 is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.

Step-by-Step

How to use Image to Base64

1

Feed a file into the Drop an image to encode target; any image type is allowed, and 8 MB is the ceiling.

2

Read the Data URI tab, which shows the encoded string and its length as a percentage of the original file size.

3

Switch to the HTML tab for a ready-made <img> tag, or the CSS tab for a background-image rule.

4

Use the copy button on any tab to put the result on your clipboard.

Key Capabilities
  • Encodes any image format the browser can read, keeping the original MIME type in the data URI header
  • Displays the encoded length and its exact percentage of the source file size
  • Generates three outputs: the raw data URI, a complete <img> tag, and a CSS background-image rule
  • Refuses files over 8 MB and explains why, instead of attempting an encode that would stall the page
Common Use Cases
  • A front-end developer inlining a small SVG or icon so a single HTML file has zero external requests.
  • A designer embedding a background texture in an email template, where the client cannot reference a hosted asset.
  • A developer building a self-contained offline page that must work from a file:// URL with no server.
Clear Answers

Frequently Asked Questions

Why is my data URI a third bigger than the file?
Base64 turns every three bytes into four printable characters, so the encoded string runs about 33% longer. That overhead is unavoidable in the format — it is the price of making binary safe to carry inside text.
Should I embed every image this way?
No. Inline data URIs cannot be cached separately, so a repeated logo becomes a repeated payload on every page load. It makes sense for small icons, one-off graphics, and single-file documents, and works against you on anything large or reused.
Does this re-encode or optimise my image first?
No. The bytes are read as they are and re-expressed in base64. If you want a smaller payload, compress the file first and then encode the result.
Is my image uploaded?
Not at all. A local file reader turns the bytes into base64 inside the page, and the Network panel stays quiet while it happens.