ICO vs PNG: differences and when to use each

Updated: 2026-10-27 · AnyToolsKit

PNG is a single image. ICO is a container that can hold many images — often PNGs themselves. Which one you need depends on where the icon goes: Windows and legacy tools want ICO, the modern web is happy with PNG and SVG.

Quick comparison

When to use ICO

• Application icons for Windows executables, installers and shortcuts.
• Custom folder and drive icons.
• The classic /favicon.ico at your site root, for maximum compatibility.
• Any time one file must provide several sizes that were tuned separately.

When to use PNG

• Favicons in modern browsers (<link rel="icon" type="image/png">).
• Apple touch icons and web app manifest icons — these must be PNG.
• App stores, social profiles, documentation, and anything that is not Windows-specific.
• Your master artwork, which you later convert to other formats.

File size

A favicon.ico with 16, 32 and 48 px BMP entries is around 15 KB. Using PNG entries for every size can shrink it to 2–5 KB. Separate PNG files are similar in size but need one HTTP request each. For a favicon either is fine — the difference is negligible on today’s connections.

Converting between them

• PNG → ICO: use PNG to ICO. Transparency is preserved and you choose the sizes.
• ICO → PNG: use ICO to PNG to extract every image inside the file, individually or as a ZIP.
• Many files at once: both tools accept multiple files and give you a ZIP.