Convert PNG to ICO — Free, Fast & Private
ICO is the odd one out among image formats: it is not really an image format at all, but a directory. A single .ico file opens with a small table of contents and then carries several complete images at different resolutions, which is why the same file can be a crisp 16px icon in a browser tab and a detailed 256px tile in Windows Explorer. This tool converts your png to ico the proper way — it renders your source at each size you tick, then packs the results into that one multi-resolution container. Everything runs in your browser; the file never leaves your device.
PNG is the ideal starting point because it is lossless and carries an alpha channel, and both properties survive the trip. If your source is a JPG or WebP the tool accepts those too — though a JPG has no transparency to preserve, so its icon will have a solid background unless you convert the JPG to PNG and clean it up first.
Why .ico still exists in 2026
The format is thirty years old and refuses to die because three ecosystems still ask for it by name. Browsers request /favicon.ico from every site root as a hard-wired fallback, and pinned sites and bookmarks on Windows read it directly. Windows itself uses ICO everywhere — application icons, shortcuts, folder customisation via desktop.ini all want .ico, not PNG, and a program compiled with a PNG where its icon resource should be simply shows the default executable glyph. And a long tail of older software — email clients, RSS readers, intranet tooling — understands ICO and nothing newer. None of these will accept a renamed PNG: the container really is checked.
PNG entries vs BMP entries — what this tool writes, honestly
Inside an ICO container, each embedded image can be stored in one of two ways. The original convention is an uncompressed BMP with a separate 1-bit transparency mask — bulky, but readable by every version of Windows back to 3.0. Since Windows Vista (2007), entries can instead be complete PNG files stored byte-for-byte, which compress dramatically better and carry full 8-bit alpha instead of a hard on/off mask. This tool writes PNG entries only. That is the right trade for almost everyone: every modern browser and every supported version of Windows read PNG entries, and files come out a fraction of the size — a four-resolution icon lands in tens of kilobytes rather than hundreds. The one thing PNG entries cannot do is satisfy Windows XP-era software, which predates the convention. If you are building icons for genuinely ancient systems, you need a BMP-entry icon editor; we would rather say that plainly than ship files four times larger to accommodate an operating system retired in 2014.
Choosing which sizes to embed
The checkboxes exist because different destinations read different entries. 16 and 32px are the browser-tab pair and the reason favicons exist; 48px serves desktop shortcuts and Windows list views; 256px is what Windows Vista and later use for large tiles and Explorer's big-icon views. For a website favicon, 16/32/48 is the classic trio and 256 is optional weight. For a Windows application icon, keep all four ticked: the shell picks whichever entry matches the display context and scaling factor, and a missing size means Windows scales the nearest one with visible softening. Each size renders independently from your source with stepped downscaling, so fine edges stay clean at 16px.
Transparency survives the conversion
Because the embedded images are real PNGs, your source's alpha channel passes through untouched — soft shadows, anti-aliased edges, and partial transparency all render correctly against any tab colour or desktop wallpaper. Non-square sources are centered on a transparent square canvas rather than cropped or stretched, so a wide wordmark arrives letterboxed but complete. One practical note: icons look best when the artwork nearly fills the square, so crop excess padding out of the source first — and if the source PNG itself is a heavyweight export, compressing the PNG is worth doing for the copy you keep.
One direction only
This page converts PNG into ICO — it does not extract images back out of .ico files. No browser exposes an ICO decoder to web pages, so an ico-to-png tool would need a hand-rolled parser for a format with three decades of malformed files in the wild; we would rather not offer it than offer it badly. Likewise, if what you actually need is the full favicon deployment — apple-touch-icon, the manifest PNGs, and the HTML tags — the favicon generator produces the whole set around the same ICO engine this page uses.