ICO vs PNG Favicons: Which Should You Use?
TL;DR
Use both. ICO is a multi-size container that Windows and older browsers require; PNG is a single-size image that modern browsers prefer for its small size and crisp rendering. The recommended setup links an ICO plus 16×16 and 32×32 PNGs.
Every favicon guide mentions ICO and PNG, but few explain the actual difference — and whether you still need a format that dates back to 1995. This article covers what each format is, where each is required, and what to ship in 2026.
What is an ICO file?
ICO is the native Windows icon format, originally created in 1995. Its defining feature is that a single .ico file can contain multiple sizes and color depths — typically 16×16, 24×24, 32×32, 48×48 and up to 256×256 frames. Windows reads the directory inside the file and picks the sharpest frame for each context.
Inside the container, images can be stored as BMP-like DIB data or, in modern .ico files (Vista and later), as PNG data. A multi-resolution ICO is how favicon.ico serves tabs, the taskbar and the start menu from one file.
What is a PNG favicon?
PNG is a single-image format with lossless compression and full alpha transparency. A PNG favicon is simply a square PNG — commonly 16×16, 32×32 or 180×180 — linked with a <link rel="icon"> tag. It is smaller than an equivalent ICO, renders crisply on high-DPI screens, and is the format modern browsers prefer when both are available.
ICO vs PNG at a glance
| Property | ICO | PNG |
|---|---|---|
| Multi-size in one file | Yes (16–256 px) | No (one size per file) |
| Transparency | Yes | Yes |
| Compression | Older versions lossless (DIB); modern use PNG inside | Lossless (deflate) |
| Windows / legacy support | Required | Partial |
| Modern browser support | Good | Excellent |
| Typical file size at 32×32 | Larger (multiple frames) | Smaller |
| High-DPI rendering | Good with multiple frames | Excellent |
Do modern browsers still need ICO?
Mostly no. Chrome, Firefox, Edge and Safari all support PNG favicons and will use a linked PNG over an ICO. The main reasons to keep an ICO are:
- Windows Explorer and the Windows taskbar/start menu still expect ICO files.
- Legacy browsers and some older devices ignore PNG favicons entirely.
- Automatic discovery: browsers request
/favicon.icoat the site root even when no link tag exists, so a root ICO is a free safety net.
What about SVG favicons?
SVG favicons (<link rel="icon" type="image/svg+xml">) scale perfectly at any size and are supported by Chrome, Firefox, Edge and Safari as of 2026. They are a great enhancement, but they don't replace ICO/PNG — older browsers ignore SVG entirely, so always ship a PNG/ICO fallback. See the Favicon Size Guide 2026 for the full size-by-platform table.
The recommended combination
For maximum compatibility with minimal effort, link these files in this order:
<link rel="icon" type="image/x-icon" href="/favicon.ico">
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">
<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">
<link rel="manifest" href="/site.webmanifest">The ICO covers Windows and legacy browsers; the PNGs cover modern high-DPI screens; the Apple touch icon and manifest cover iOS, Android and PWAs. A generator like FaviconX produces all of these and the HTML snippet automatically.
Next, learn the exact pixel sizes: Favicon Size Guide 2026, or jump straight to the tool: Create your favicon set.