TontonTools

ICO Converter

Convert images to multi-size ICO files — icons done properly.

100% Free No signup Privacy-friendly Image Tools
Updated Sep 2026

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How to use ICO Converter

  1. Upload a square image — 256px+ PNG with transparency is ideal.
  2. Convert — the standard size ladder is generated automatically.
  3. Download the .ico — one file, all resolutions.
  4. Deploy: as /favicon.ico for sites, or as the icon resource for Windows apps and shortcuts.

What is ICO Converter?

An ICO converter builds proper Windows icon files from your images — exploiting ICO's defining feature: one .ico can contain multiple resolutions (16, 32, 48, up to 256px), letting every consumer (browser tab, bookmark bar, Windows Explorer at any view size, taskbar) pick its ideal rendition instead of scaling one image badly.

That multi-size packaging is what separates a "proper" icon from a single-size conversion: Windows especially renders icons at many sizes, and a 256-only or 32-only ICO looks wrong somewhere. The converter generates the ladder from your source automatically.

About the ICO Converter

Upload your image — square PNG with transparency is the ideal source — and download an ICO containing the standard resolution set.

Where multi-size ICOs matter: website favicons at their most robust (16/32/48 covering tabs, bookmarks and pinned sites), Windows application icons (the .exe's icon renders from 16px list views to 256px tiles — apps need the full ladder), desktop shortcuts and folder customization, and Electron/desktop-app packaging which expects a complete ICO.

Source-image guidance: start at 256×256 or larger and square (downscaling generates the smaller rungs cleanly; upscaling a small source helps nothing), keep transparency (alpha survives into every size), and design for the bottom rung — the 16px version is what most people see most often, so the simplest-bold-shape rule governs. Icons that look great at 256 and muddy at 16 are backwards.

Frequently Asked Questions

Because consumers render icons at many sizes — 16px tabs, 32px bookmarks, 48px+ Explorer views, 256px tiles. Embedded per-size renditions beat runtime scaling every time; that's ICO's reason to exist.
Square, 256×256 or larger, PNG with transparency, and designed simply enough to survive 16px. The converter downscales cleanly; it can't add detail or fix busy art.
The favicon set: 16/32/48. For Windows apps, add 64/128/256. Extra sizes cost little; missing ones show as blurry scaling somewhere in the OS.
Yes — modern ICO carries full alpha per rendition, so soft edges and transparent backgrounds survive across the ladder.
Right-click → Properties → (Shortcut or Customize tab) → Change Icon → browse to your .ico. Windows reads whichever embedded size each context needs.

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