Convert an Image to Base64 Online
This free image to Base64 converter turns any image into a Base64-encoded data URI you can paste directly into HTML or CSS. Choose an image and press Convert to get the string, then copy it. The encoding happens in your browser, so your image is never uploaded — private and instant.
How to Convert an Image to Base64
- Choose a PNG, JPG, WebP, GIF, or SVG image.
- Press Convert to Base64.
- Copy the data URI from the output box.
What a Base64 Data URI Is
A data URI embeds a file’s contents directly in text using Base64 encoding, in the form data:image/png;base64,iVBORw0K.... Instead of linking to a separate image file, you put the whole image inline in your HTML img tag or CSS url(). The browser decodes the Base64 back into the image. This trades a larger HTML/CSS file for one fewer network request, which can speed up loading for small images.
Why Use Base64 Images?
Embedding small images as Base64 has real advantages. It removes a separate HTTP request, which for tiny icons and backgrounds can improve performance, especially over slow connections. It keeps an asset self-contained — useful in a single-file HTML email, a bookmarklet, or a component where you do not want external dependencies. It also avoids broken-image issues since the data travels with the markup. Developers use it for icons, small logos, placeholder graphics, and CSS background sprites.
When Not to Use Base64
Base64 is best for small images only. Encoding inflates the data by about 33%, and large embedded images bloat your HTML or CSS, are not cached separately by the browser, and must be re-downloaded every time the page loads. For photos and large graphics, a normal linked image file is more efficient because it can be cached and loaded in parallel. A good rule of thumb is to Base64-encode images under a few kilobytes — icons and tiny graphics — and link everything larger.
Private, In-Browser Encoding
This converter reads and encodes your image locally in the browser, so it never leaves your device — safe for any image, with no upload waits or limits beyond your browser. The output is a ready-to-paste data URI; the tool also shows its length so you can judge whether the image is small enough to be worth embedding.
Frequently Asked Questions
How do I convert an image to Base64?
Choose your image, press Convert to Base64, and copy the data URI from the output box.
How do I use a Base64 image?
Paste the data URI as the src of an img tag, or inside url() in CSS. The browser decodes it automatically.
Is my image uploaded anywhere?
No — the encoding happens entirely in your browser, so your image stays on your device.
Performance: When Base64 Helps and Hurts
The appeal of a Base64 data URI is eliminating a network request. Every separate image on a page is normally a round trip to the server, and for tiny assets — an icon, a 1px background, a small logo — the overhead of that request can outweigh the size of the file itself. Embedding such images inline means they arrive with the HTML or CSS and render immediately, with no extra requests and no risk of a broken-image icon. This is especially useful in self-contained contexts like HTML email, where external images are often blocked, and in single-file documents or components that must not depend on outside assets.
The trade-offs matter just as much. Base64 encoding makes the data roughly 33% larger than the original binary, and inlined images cannot be cached separately by the browser — they are re-downloaded as part of the page every time, whereas a linked image file is cached once and reused across pages. Inlining large images also bloats your HTML or CSS and can delay rendering. The sensible rule is to embed only small images (a few kilobytes or less) and link to everything bigger. The length figure this tool reports helps you make that call: if the data URI is very long, the image is probably better served as a normal file.