How to Convert Transparent PNG Images to ICO Icons (Free Windows Tool + Size Guide)

People search for things like convert PNG to ICO, transparent PNG to icon, or make Windows icon from PNG when they need a clean icon for an app, shortcut, or folder.

It sounds simple, but a lot of online converters produce blurry icons, break transparency, or force subscriptions.

Quick truth: Windows icons work best when they come from high-quality PNG images and are converted properly. Garbage in = garbage icon.

What is an ICO file?

An ICO file is the image format Windows uses for:

  • Application icons
  • Desktop shortcuts
  • Folder icons
  • Taskbar / Start menu icons

Unlike a normal image, an ICO is designed to render cleanly at small sizes and support transparency.

Why start with transparent PNG images?

PNG files support transparency and high resolution, which makes them ideal source images for icons.

If your PNG has:

  • Clean edges
  • Transparent background
  • High resolution (512×512 or larger)

You’ll get much better ICO results.

Transparent PNG image example
High-resolution transparent PNG files produce the best Windows icons.

Online PNG to ICO converters: what usually goes wrong

Most online converters suffer from one or more of these issues:

  • Blurry scaling
  • Broken transparency (black or white backgrounds)
  • Low-resolution exports unless you pay
  • Daily limits
  • Forced subscriptions
  • Privacy concerns (you must upload your images)

They’re fine for quick tests, but not great for repeat use.

Better option: offline PNG to ICO conversion

An offline converter runs directly on your PC:

  • No uploading
  • No limits
  • No subscriptions
  • Consistent quality
  • Works with folders

This is why I built a small free Windows utility specifically for PNG → ICO conversion.

Download PNG to ICO Converter (Free)

Open Instructions for Toms PNG 2 ICO Converter

How the PNG to ICO tool works

  1. Run the EXE
  2. Drag & drop PNG files or a folder
  3. Select output icon size
  4. Choose Pad or Crop (for non-square images)
  5. Click Convert

The tool automatically creates an _icons folder next to your images and saves the ICO files there.

PNG to ICO converter app interface
Drag, choose size, convert. No setup required.

Pad vs Crop (non-square PNGs)

If your PNG isn’t square, icons still must be square.

Pad (recommended)

  • Keeps entire image
  • Adds transparent space
  • Best for logos and badges

Crop

  • Center crops to square
  • Fills space more aggressively
  • Can cut off edges

If your logo has text near the edges, use Pad mode.

Best Windows icon sizes (and what they’re used for)

Size Best use
16×16 Small toolbar icons, legacy UI
24×24 Some application UI elements
32×32 Common app icon size
48×48 Desktop shortcuts
64×64 High-DPI UI elements
128×128 Large previews
256×256 Windows Explorer large icons (recommended)

Tip: If unsure, use 256×256. Windows scales down cleanly.

Best practices for clean icons

  • Start with 512×512 or larger PNG
  • Use transparent backgrounds
  • Avoid tiny source images
  • Keep important details away from edges

Why a simple single-size ICO is usually enough

Some tools generate multi-size ICO files.

In practice, Windows handles scaling extremely well. A high-quality 256×256 ICO covers almost all modern use cases.

Simple files = fewer problems.

Common uses for PNG → ICO conversion

  • Custom app icons
  • Branding shortcuts
  • Folder theming
  • Side-project EXE icons
  • Game mod icons

Troubleshooting

  • Blurry output: Use higher resolution PNG
  • Black background: Source PNG isn’t transparent
  • No output: Check _icons folder
  • Windows icon not updating: Restart Explorer or clear icon cache

Recommended workflow

  1. Create high-res transparent PNG
  2. Convert to 256×256 ICO
  3. Assign icon in Windows
  4. Done