Favicon File Formats: ICO vs PNG vs SVG Complete Guide 2024

The Three Main Favicon Formats

Modern web favicons use three primary file formats: ICO (Internet Explorer legacy), PNG (universal standard), and SVG (emerging modern standard). Each has specific use cases and browser support levels.

ICO Format

Legacy

Microsoft's icon format. Can contain multiple sizes in one file.

Best for: IE11 and older browser support

PNG Format

Recommended

Universal image format with transparency support. Industry standard.

Best for: All modern browsers and devices

SVG Format

Modern

Vector format that scales perfectly at any size. Smallest file size.

Best for: Chrome, Firefox, modern browsers

ICO Format: The Original Favicon Format

The ICO format was created by Microsoft for Windows icons and was adopted as the first favicon format when Internet Explorer 5 introduced favicon support in 1999.

ICO Format Advantages

Multi-resolution support: One ICO file can contain 16x16, 32x32, and 48x48 versions. Browser picks the best size automatically.
Maximum compatibility: Works in Internet Explorer 5-11, Edge Legacy, and all modern browsers as fallback.
No HTML required: `favicon.ico` in root directory is detected automatically by browsers without link tags.

ICO Format Limitations

Maximum size: 256x256 pixels

Can't be used for large icons like Apple Touch or Android home screen icons.

Larger file size

Multi-resolution ICO files (16+32+48) are often 5-15 KB vs 1-3 KB for single PNG.

Difficult to create

Requires specialized tools. Most image editors can't export true ICO format.

ICO Format Browser Support

Browser	Support	Notes
Chrome	✅ Full	Prefers PNG, falls back to ICO
Firefox	✅ Full	Supports multi-resolution ICO
Safari	✅ Full	Prefers PNG for Retina displays
Edge	✅ Full	Native ICO support
IE 11	✅ Required	Only supports ICO, not PNG

PNG Format: The Modern Standard

PNG (Portable Network Graphics) has become the de facto standard for favicons on modern web. It supports full transparency, high resolution, and is universally supported.

Why PNG is Recommended

High resolution support: Can be any size up to 2048x2048+ for Retina displays and large touch icons.
Alpha transparency: Perfect for logos with transparent backgrounds. Adapts to light/dark browser themes.
Small file sizes: Optimized PNGs are typically 1-3 KB for 32x32, 3-8 KB for 192x192. Smaller than equivalent ICO.
Easy to create: Every image editor supports PNG export. Simple workflow from design to deployment.
Universal platform support: Required for iOS, Android, PWA, Windows tiles. One format for everything.

PNG Bit Depth Considerations

PNG-8 (8-bit, 256 colors)

Pros:

✓ Smallest file size (often 50% smaller than PNG-24)
✓ Perfect for simple logos with limited colors
✓ Supports full transparency (1-bit alpha)

Cons:

✗ No semi-transparency (no smooth edges on transparent logos)
✗ Limited to 256 colors
✗ Can show banding on gradients

Use for: Simple, flat icon designs without gradients.

Recommendation: Use PNG-24 for favicons. The file size difference is negligible (1-2 KB) and you get perfect transparency and smooth edges.

SVG Format: The Future of Favicons

SVG (Scalable Vector Graphics) is the newest favicon format. It's resolution-independent, infinitely scalable, and has the smallest possible file size for vector graphics.

SVG Favicon Advantages

Perfect Scaling

Looks crisp at any size from 16x16 to 512x512. One file for all resolutions.

Tiny File Size

Typical SVG favicon: 300-800 bytes vs 2-5 KB for PNG. 85-95% size reduction.

Dark Mode Support

Can include CSS media queries to change colors based on user's theme preference.

Dynamic Updates

Can be animated or updated via JavaScript for notifications or status changes.

SVG Favicon with Dark Mode

One of the most powerful SVG features is automatic color adaptation based on the browser's theme:

<!-- favicon.svg -->
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32">
  <style>
    .logo { fill: #000000; }
    @media (prefers-color-scheme: dark) {
      .logo { fill: #FFFFFF; }
    }
  </style>
  <circle class="logo" cx="16" cy="16" r="14"/>
</svg>

This SVG automatically switches from black in light mode to white in dark mode.

SVG Favicon Limitations

Safari: No support

Safari (macOS and iOS) does not support SVG favicons at all. PNG fallback required.

No mobile home screen icons

iOS, Android, PWAs all require PNG format. SVG only works for in-browser tab icons.

Not ideal for complex graphics

SVG works best for simple geometric shapes. Photos or complex logos should use PNG.

SVG Browser Support

Browser	Desktop	Mobile
Chrome	✅ v80+ (2020)	✅ v80+ (2020)
Firefox	✅ v41+ (2015)	✅ v41+ (2015)
Safari	❌ No support	❌ No support
Edge	✅ v79+ (2020)	✅ v79+ (2020)
Opera	✅ v67+ (2020)	✅ v67+ (2020)

Format Comparison: Which to Use?

Use Case	Recommended Format	Why?
Browser tab icon	PNG + SVG	SVG for modern browsers, PNG fallback
iOS home screen	PNG only	Apple requires PNG (apple-touch-icon)
Android home screen	PNG only	Android manifest requires PNG
PWA icons	PNG only	Manifest.json spec requires PNG
Windows tiles	PNG only	browserconfig.xml uses PNG
IE11 support needed	ICO required	IE11 doesn't support PNG favicons

Recommended Multi-Format Strategy

The Complete Setup (All Browsers + Devices)

<!-- SVG for modern browsers with dark mode -->
<link rel="icon" type="image/svg+xml" href="/favicon.svg">

<!-- PNG fallback for Safari, mobile devices -->
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">

<!-- ICO fallback for IE11 (optional if you need IE support) -->
<link rel="icon" type="image/x-icon" href="/favicon.ico">

<!-- Apple Touch Icons -->
<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">

<!-- Android/PWA -->
<link rel="manifest" href="/manifest.json">

This setup provides maximum compatibility: SVG for modern browsers, PNG for Safari and mobile, and ICO for legacy IE11.

Converting Between Formats

Converting PNG to ICO

Online Tools:

• ICO Converter
• Convertio PNG to ICO
• Our favicon generator (creates multi-resolution ICO automatically)

Desktop Tools:

• ImageMagick: convert favicon.png favicon.ico
• GIMP: File → Export As → Select ICO format

Tip: Multi-resolution ICO files (16+32+48 in one file) provide better quality at different sizes. Use specialized tools for this.

File Size Optimization

Optimizing favicons reduces page load time. Here are target file sizes for each format:

ICO Files

16x16 only: <1 KB
16+32: 2-4 KB
16+32+48: 5-15 KB

Tool: ImageMagick with quality settings

PNG Files

16x16: <1 KB
32x32: 1-3 KB
180x180: 3-8 KB
512x512: 8-20 KB

Tools: TinyPNG, pngquant, OptiPNG

SVG Files

Simple icon: 200-500 bytes
Complex icon: 1-3 KB
Very complex: 3-10 KB

Tools: SVGO, SVGOMG (online)

PNG Optimization Commands

# OptiPNG (lossless compression)
optipng -o7 favicon-32.png

# pngquant (lossy, better compression)
pngquant --quality=80-100 favicon-32.png -o favicon-32-optimized.png

# ImageMagick (resize + optimize)
convert input.png -resize 32x32 -strip -quality 95 favicon-32.png

SVG Optimization

# SVGO (Node.js tool)
npm install -g svgo
svgo favicon.svg -o favicon-optimized.svg

# Online tool: https://jakearchibald.github.io/svgomg/
# Upload SVG, toggle optimization options, download result

Format Decision Flowchart

Do you need IE11 support?

→ Yes: Use ICO + PNG

→ No: Continue...

Is your logo simple geometric shapes?

→ Yes: SVG + PNG fallback (recommended)

→ No: PNG only

Do you want dark mode adaptation?

→ Yes: SVG with CSS media query + PNG fallback

→ No: PNG only is fine

Universal recommendation for 2024:

→ PNG for all sizes (works everywhere)

→ Optional: Add SVG for modern browsers

→ Optional: Add ICO only if IE11 needed

Generate All Formats Automatically

Our favicon generator creates PNG, ICO, and SVG formats from your logo. Get all sizes and formats optimized and ready to deploy in seconds.

Create All Formats Now →

Favicon File Formats: ICO vs PNG vs SVG