Favicon ICO vs PNG: Which Format Should You Use?

When you set up a favicon, you quickly realize there is not just one file format to worry about — there are three common options, each with different browser support, capabilities, and use cases. Should you serve a .ico file, a .png, or an .svg? The honest answer is: ideally, all three. But understanding what each format does helps you make the right tradeoffs for your situation.

The ICO Format

ICO is the original favicon format. Microsoft created it for use in Windows, and Internet Explorer adopted it when it introduced favicons in 1999. The .ico extension stands for “icon,” and the format has a distinctive feature that other image formats lack: it is a container file that can hold multiple images at different resolutions inside a single file.

A single favicon.ico can contain a 16×16 image, a 32×32 image, a 48×48 image, and more — all bundled together. When a browser requests the file, it picks the size that best fits its context. This multi-resolution capability was designed for Windows, where icons need to look correct at many different sizes depending on the UI context.

Why ICO Is Still Essential

Despite being a format from 1999, favicon.ico remains a fundamental part of favicon support for one key reason: browsers automatically look for it at the root of your domain, even without any HTML declaration.

When a browser loads a page and finds no <link rel="icon"> tag, it makes an automatic request to https://yourdomain.com/favicon.ico. If the file exists, the favicon appears. This behavior is deeply embedded in how browsers work, and it means that placing a favicon.ico at your site’s root is the most universally reliable way to ensure your favicon shows up everywhere.

Beyond the automatic fallback, favicon.ico is the only format that works in Internet Explorer, which some organizations — particularly enterprise environments — still use. If your audience includes users on legacy enterprise systems, an ICO file is your only path to favicon support for them.

ICO Limitations

The main downside of ICO is that creating and editing it requires tools that understand the format. You cannot just rename a PNG to .ico and expect it to work correctly — the file structure is genuinely different. ICO also does not support animation, and its color mode support, while broad, is older and less flexible than PNG.

The PNG Format

PNG (Portable Network Graphics) is a standard raster image format that all modern browsers understand. PNG supports transparency, has excellent color fidelity, and can be created and edited with any image editor.

For favicons, PNG has become the preferred format for explicit declarations. The <link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png"> approach is clean, readable, and works in Chrome, Firefox, Safari, and Edge.

Why PNG Is Cleaner for Explicit Declarations

When you are linking your favicon via HTML, PNG is simpler to work with than ICO. You can serve separate files for each size — favicon-16x16.png and favicon-32x32.png — and let the browser’s sizes attribute handling decide which to use. This is more transparent than an ICO container, and it means you can update one size without regenerating the entire bundle.

Apple’s touch icon system uses PNG exclusively. The apple-touch-icon.png file must be a PNG, and it should have a solid opaque background rather than transparency (Apple’s system applies its own rounded corner mask and does not handle transparency well in this context).

PNG Limitations

A PNG file is a single resolution. A 32×32 PNG is always 32×32 — there is no built-in multi-resolution container like ICO provides. This is why you typically end up with several separate PNG files (16×16, 32×32, 180×180, 192×192, 512×512) rather than one file that covers everything.

PNG also provides no way to adapt to the user’s color scheme. If you want your icon to look different in dark mode, you need a different solution — which brings us to SVG.

The SVG Format

SVG (Scalable Vector Graphics) is the newest favicon format and the most capable. Unlike ICO and PNG, which are raster formats (pixels arranged in a grid), SVG is a vector format. The image is defined as mathematical paths and shapes that can be rendered at any resolution without quality loss.

Why SVG Is the Future of Favicons

The resolution-independence of SVG solves the multi-size problem entirely. One SVG file looks perfect at 16×16, 32×32, 64×64, and beyond. There is no quality degradation, no need to manage multiple files for different pixel densities, and no visible blurriness on high-DPI retina screens.

More importantly, SVG supports the prefers-color-scheme media query right inside the file. This means your favicon can automatically switch between a light version and a dark version depending on whether the user has set their OS to dark mode. Here is what that looks like inside an SVG:

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
  <style>
    circle &#123; fill: #1a1a1a; &#125;
    @media (prefers-color-scheme: dark) &#123;
      circle &#123; fill: #ffffff; &#125;
    &#125;
  </style>
  <circle cx="50" cy="50" r="45"/>
</svg>

No other favicon format can do this.

SVG Limitations

The critical limitation of SVG favicons is Safari. As of mid-2026, Safari does not support SVG favicons. This means that any user on Safari — which includes all browsers on iOS due to Apple’s browser engine policy — will not see your SVG favicon. This is why SVG cannot be your only favicon format.

SVG also requires that your icon is actually defined as vector data. If your logo exists only as a raster image (a JPG or PNG), you cannot create an SVG favicon without redrawing the artwork as vectors. For icons based on simple geometric shapes or text, this is easy. For complex illustrations, it can require significant effort.

The Best Practice: Serve All Three

Rather than choosing one format, the standard recommendation is to use all three in combination, with fallback behavior handling everything automatically:

<!-- Fallback for any browser, and for automatic root-file lookup -->
<link rel="icon" type="image/x-icon" href="/favicon.ico">

<!-- SVG for modern browsers (Chrome, Firefox, Edge) — supports dark mode -->
<link rel="icon" type="image/svg+xml" href="/favicon.svg">

<!-- PNG fallback for browsers that prefer explicit PNG declarations -->
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">

<!-- Apple touch icon (PNG required) -->
<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">

Browsers work through this list and use the best option they support. A modern Chrome browser picks the SVG. Safari picks the PNG or ICO. Any browser that does not understand any of the explicit declarations falls back to the root favicon.ico.

Quick Decision Guide

Situation	What to Use
You want maximum compatibility	ICO (root file + HTML declaration)
You are only targeting modern browsers	PNG
You want dark mode support	SVG (with ICO fallback)
You are building a PWA	PNG (in web manifest)
You want home screen icons on iOS	PNG (apple-touch-icon)
You want the full solution	ICO + SVG + PNG

A favicon generator handles all of this for you. Provide one source image, and it produces every format and size you need, along with the HTML snippet to paste into your <head>. There is no reason to choose just one format when the tooling makes serving all three straightforward.