SVG vs ICO: The Best Format for Favicons and Icons
ICO has been the favicon standard for decades. SVG favicons are now supported by all modern browsers. Here's what you need to know.
What Is ICO?
ICO is a Microsoft-developed format for Windows icons and browser favicons. An ICO file is actually a container that holds multiple raster images at different resolutions (typically 16×16, 32×32, 48×48, and 256×256). Browsers download the favicon.ico from the root of a website and use the most appropriate size.
- Container format — holds multiple resolutions
- Raster-based at each embedded size
- Universal compatibility, including very old browsers
- Required for some Windows application icons
- No scalability — each size is a separate raster image
SVG vs ICO for Favicons
Modern browsers now support SVG favicons, which offer significant advantages over ICO.
| Feature | SVG Favicon | ICO Favicon |
|---|---|---|
| Scalability | Infinite — one file, all sizes | Fixed sizes embedded in container |
| File size | Very small (single file) | Larger (multiple embedded bitmaps) |
| Dark mode support | Yes (via CSS media queries) | No |
| Browser support | All modern browsers | Universal, including IE |
| Editability | Text editor or vector app | Requires icon editor |
| Transparency | Full alpha | 1-bit or 8-bit alpha |
| Recommended for | Modern websites | Legacy support and Windows apps |
Why SVG Favicons Are Now Preferred
SVG favicons (declared with `<link rel='icon' type='image/svg+xml' href='favicon.svg'>`) scale perfectly on retina and high-DPI displays without needing a 2x version. They also support CSS `prefers-color-scheme`, allowing your favicon to automatically switch between a light and dark version. A single SVG favicon replaces the entire set of ICO, PNG, and Apple Touch Icon files that developers used to manage.
- One file works at all sizes and pixel densities
- Supports dark/light mode with CSS media queries
- Inline SVG code can be smaller than any ICO file
- Supported by Chrome, Firefox, Safari, and Edge
When ICO Is Still Necessary
Internet Explorer does not support SVG favicons. If you have a meaningful number of IE users, you still need a favicon.ico fallback. Windows also uses ICO format for taskbar and desktop application icons. For maximum compatibility, many developers use both: an SVG favicon as the primary and a favicon.ico as a fallback.
Creating an SVG Favicon from a Logo
To create an SVG favicon, start with your logo in SVG format. Simplify it for small sizes — remove fine details that disappear at 16×16. Upload your PNG or raster logo to ImageToSVG.com to get a clean SVG base, then simplify it in a vector editor for use as a favicon.
Frequently Asked Questions
Can I use SVG as a favicon in 2025?
Yes. All modern browsers — Chrome, Firefox, Safari, and Edge — support SVG favicons. Use `<link rel='icon' type='image/svg+xml' href='/favicon.svg'>` in your HTML.
Do I still need a favicon.ico file?
For modern sites, an SVG favicon is sufficient for most users. However, keeping a favicon.ico as a fallback at the root of your domain ensures compatibility with Internet Explorer and some older crawlers.
How do I convert an ICO to SVG?
Extract the highest-resolution PNG from the ICO file (many online tools do this), then upload the PNG to ImageToSVG.com to trace it into a vector SVG.
What size should an SVG favicon be?
SVG favicons don't have a fixed size — they scale to whatever the browser needs. Design your SVG on a square canvas (e.g., 100×100 or 32×32 viewBox) and it will render correctly at any size.
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