Image to Base64 Converter
Upload any image and instantly convert it to a Base64-encoded data URL. Copy the result to embed images directly in CSS, HTML, or JSON.
Drop an image here, or click to browse
PNG, JPG, GIF, WebP, SVG, AVIF …
FAQ
What is a Base64 data URL?▼
A data URL encodes a file as a Base64 string directly inside a URL with the format data:[type];base64,[data]. This lets you embed images in HTML, CSS, or JSON without a separate file request.
Does my image get uploaded anywhere?▼
No. The conversion is done entirely in your browser using the FileReader API. Your image never leaves your device.
Why is the Base64 output larger than the original file?▼
Base64 encoding represents every 3 bytes of binary data as 4 ASCII characters, which increases the size by approximately 33%.
Frequently Asked Questions
What is a Base64 data URL?
A data URL embeds a file directly as a Base64 string with the format data:[mime-type];base64,[data]. This eliminates a separate HTTP request and is useful for CSS, email HTML, and API payloads.
Is my image uploaded to a server?
No. The conversion is done entirely in your browser using the FileReader API. Your image never leaves your device.
Which image formats are supported?
PNG, JPEG, GIF, WebP, SVG, BMP, and AVIF are all supported. The output preserves the original MIME type in the data URL.
What is a Base64 Data URL?
A data URL (or data URI) embeds a file\'s binary content directly into a string using Base64 encoding, with the format:
data:[mime-type];base64,[encoded-data] # Example (small PNG): data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA...
The browser treats a data URL exactly like a regular URL — you can use it in <img src>, CSS background-image, or as a link href for client-side download triggers.
When to Use Base64 Images
| Use case | Verdict | Notes |
|---|---|---|
| Email HTML templates | ✅ Recommended | No external request blocked by email clients |
| Critical above-fold images | ✅ Acceptable | Avoids extra HTTP request; use for tiny images only |
| API payloads (REST/GraphQL) | ✅ Common | When binary upload is not supported |
| Large hero images on pages | ❌ Avoid | +33% size overhead + blocks HTML parsing |
| CSS background sprites | ⚠️ Legacy | HTTP/2 multiplexing makes sprites less necessary |
The Base64 Size Overhead
Base64 encoding increases file size by approximately 33%: every 3 bytes of binary become 4 ASCII characters. A 100 KB image becomes ~133 KB as a Base64 string. This overhead is non-compressible (Base64 has low entropy), so Gzip/Brotli provides minimal benefit after encoding.
For files larger than ~5 KB, a regular<img src="/file.png">with HTTP/2 is almost always more efficient than a data URL.