Image to Base64 Converter — Data URL, HTML & CSS Snippets

How to convert an image to Base64

1. Click the file button and select the image from your device — PNG, JPG, GIF, WebP, or SVG.
2. Wait a moment while the tool reads the file and builds the Base64 string.
3. Copy the output string and paste it into your HTML or CSS as a data URL.
4. Optional: download the encoded text as a .txt file so you can reuse it later without converting again.

A data URL always starts with the media type, then the Base64 data, for example: data:image/png;base64,iVBOR…

A worked example, with the numbers

Say you have a small company logo as a 6 KB PNG file. You load it into the converter, and it produces the Base64 string. Base64 encoding adds roughly 33% to the file size, so the output text is about 8 KB — still tiny.

The string starts with “data:image/png;base64,iVBOR…” and continues with the encoded data. To use it in HTML, paste the whole string as the image source: <img src=”data:image/png;base64,iVBOR…”>. To use it in CSS, put it inside url(): background-image: url(“data:image/png;base64,iVBOR…”);

Now the page shows the logo without loading any separate image file. There is no second request to a server for that image, and the HTML file works even if it is opened offline or saved on its own.

When you need an image-to-Base64 converter

• HTML email templates that must be self-contained. Many email clients block external images, so inlining a small image as a data URL keeps the design intact without a separate file to host.
• Inlining tiny icons and logos to save an HTTP request. A small icon becomes part of the HTML or CSS itself, so the browser does not fetch an extra file.
• Single-file offline documents. Reports and pages that must open correctly with no internet connection can carry their images inside the file.
• Embedding small images inside JSON payloads. When an API or data file needs to include an image, a Base64 string fits naturally into a text field.
• Quick prototypes and test pages. Drop an image into the page without setting up hosting or an uploads folder first.

Limitations worth knowing

• Base64 inflates the file by about 33%, and the result cannot be cached separately by the browser — so it is only worth it for small images, roughly under 10 KB.
• Never do this with photos. A 2 MB photo becomes a 2.7 MB text string that slows page loading and eats memory.
• A long encoded string is unwieldy to edit by hand. If the image needs frequent changes, keep the original image file and convert it again after each edit.
• Large data URLs make your HTML or CSS file much bigger, which can hurt performance on slow connections more than a normal image request would.

Image to Base64 – frequently asked questions

Does Base64 make the file smaller?

No. Base64 encoding makes the file about 33% bigger. The win is fewer requests, not size — the image becomes part of the page instead of a separate download.

Which image formats are supported?

Any format your browser can read, including PNG, JPG, GIF, WebP, and SVG. The output data URL carries the correct media type for the format you chose.

How do I use the output in CSS?

Paste the string into a url() value: background-image: url(“data:image/png;base64,…”); — use the full string the tool produced, starting from “data:image/”.

Is my image uploaded to a server?

No. The tool reads the file with your browser’s built-in FileReader on your own device. Nothing is sent anywhere.

More free Image Converters

• WebP to JPG Converter
• PNG to SVG Tool
• SVG to PNG Converter
• Advanced Base Converter
• Date to Epoch Time Converter

Browse all Image Converters on Ilmhunt, or see all free online tools.