How to Convert PNG to ICO: Free Methods Explained

The ICO format has been the standard favicon format since the early days of the web. While modern browsers support PNG favicons, ICO remains essential for maximum compatibility. Here's how to convert PNG to ICO using different methods.

Why ICO Still Matters in 2026

• Universal browser support — ICO works in every browser, including very old versions of IE.
• Multi-size container — A single ICO file can contain multiple image sizes (16×16, 32×32, 48×48) — the browser picks the best one.
• Windows integration — Windows desktop shortcuts and taskbar pins use ICO format.
• Automatic fallback — Browsers look for /favicon.ico at the root of every website by default.

Method 1: Online Tool (Easiest)

The simplest way is to use Mzu favicondl's Image to Favicon tool:

1. Go to the Tools page.
2. Upload your PNG image.
3. The tool generates all favicon sizes (ICO, 16×16, 32×32, 180×180, 192×192, 512×512).
4. Download the complete package as a ZIP file.

Method 2: Command Line with ImageMagick

For developers who prefer the terminal, ImageMagick is the gold standard:

# Install ImageMagick
# macOS: brew install imagemagick
# Ubuntu: sudo apt install imagemagick
# Windows: choco install imagemagick

# Convert PNG to ICO (single size)
magick convert input.png -resize 32x32 favicon.ico

# Create multi-size ICO (recommended)
magick convert input.png -define icon:auto-resize=16,32,48 favicon.ico

The multi-size approach is best — the browser automatically selects the most appropriate size.

Method 3: Using FFmpeg

If you already have FFmpeg installed:

ffmpeg -i input.png -vf scale=32:32 favicon.ico

Method 4: Python Script

Using the Pillow library:

from PIL import Image

img = Image.open('input.png')
img.save('favicon.ico', format='ICO',
         sizes=[(16, 16), (32, 32), (48, 48)])

PNG vs ICO: When to Use Each

Feature	PNG	ICO
Modern browser support	All	All
Legacy browser support	IE 11+	All IE versions
Multiple sizes in one file	No	Yes
Transparency	Yes	Yes
File size	Smaller per size	Larger (multi-size)
Windows shortcuts	No	Yes
Auto-detection by browsers	Only if declared in HTML	/favicon.ico auto-detected

Best Practice: Use Both

The recommended approach is to provide both formats:

<!-- ICO as fallback -->
<link rel="icon" type="image/x-icon" href="/favicon.ico">

<!-- PNG for modern browsers (crisper rendering) -->
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">

Modern browsers will prefer the PNG. Older browsers and Windows shortcuts will use the ICO. You get the best of both worlds.

Tips for Best Results

• Start with a square image — Non-square images will be stretched or cropped.
• Use at least 512×512 as input — Scaling down produces better results than scaling up.
• Keep it simple — At 16px, fine details disappear. Bold shapes and high contrast work best.
• Use transparent backgrounds — Solid backgrounds look outdated in modern browser tabs.
• Test at actual size — Zoom your icon down to 16×16 pixels and check readability.