Free · no signup · never uploaded
PNG to ICO Converter
Turn a PNG into a multi-size .ico favicon right in your browser — pick the sizes, keep transparency, no upload.
Short answer
To convert PNG to ICO, drop your PNG below, choose the icon sizes you want (16–256px), and download a single .ico file containing all of them. That’s the format Windows and browser favicons use. It runs in your browser — the image is never uploaded — and transparency is preserved.
What is an .ico file?
An ICO file is a small container that can hold the same icon at several sizes — so Windows or a browser can pick the right resolution for a taskbar, a tab favicon, or a desktop shortcut. A good favicon .ico usually bundles 16, 32, and 48px; add 64–256px if you also want a high-DPI app icon.
Start from a square PNG
Icons are square, so a square PNG gives the best result. If your PNG isn’t square, it’s scaled to fit and centered with transparent padding rather than stretched. Keep the source large (256px+) so every embedded size stays crisp.
Favicon sizes in the .ico file
| Size | Where it's used |
|---|---|
| 16 × 16 px | Browser tabs, address bar, bookmarks |
| 32 × 32 px | Taskbar, desktop shortcuts, retina tabs |
| 48 × 48 px | Windows desktop icons |
| 64 × 64 px | High-DPI displays |
| 128 × 128 px | App listings and large tiles |
| 256 × 256 px | Windows Explorer extra-large icons |
A .ico file holds several resolutions in one file, and the browser or operating system picks whichever it needs. That is why a favicon should be generated from a square source image with simple, bold shapes — fine detail disappears entirely at 16 × 16.
How we calculate this
The icon is built locally in your browser — here is exactly how:
- Decode. your PNG is decoded to a bitmap in the browser (via createImageBitmap) — never uploaded to any server.
- Render each size. for every size you selected, the image is aspect-fit onto a square canvas (centered, transparent padding) and PNG-encoded.
- Pack. the PNG-encoded sizes are written into a single ICO directory (the standard .ico byte layout) that you download.
Assumptions
- Everything runs client-side; the PNG never leaves your device.
- Each embedded size is a PNG-compressed entry, so transparency is preserved.
- Non-square sources are fit and centered, not stretched.
Last reviewed: July 19, 2026
Frequently asked questions
How do I convert a PNG to ICO?+
Drop your PNG above, tick the icon sizes you want, and download the .ico. All the sizes are packed into one file, generated in your browser — the PNG is never uploaded.
Which sizes should a favicon include?+
16, 32, and 48px cover browser tabs and Windows shortcuts, which is enough for most favicons. Add 64, 128, or 256px if you also want a sharp icon on high-DPI displays or as an app icon.
Does the .ico keep transparency?+
Yes. Each size is stored as a PNG inside the .ico with its alpha channel intact, so transparent corners stay transparent — no white box behind your icon.
Does my PNG need to be square?+
It's best. Icons are square, so a square source looks right at every size. A non-square PNG is scaled to fit and centered with transparent padding instead of being stretched.
Are my images uploaded?+
No. The icon is built entirely in your browser — each size is drawn on a canvas and packed into the .ico locally. Nothing is stored or sent to a server.
Can I use this .ico as a website favicon?+
Yes. Save it as favicon.ico in your site root, or reference it with a <link rel="icon"> tag. Because it holds multiple sizes, browsers pick the best one automatically.
Related tools
- SVG to PNG — rasterize a logo SVG to PNG first.
- Image resizer — crop or resize the PNG to a square.
Icons are built entirely in your browser and never uploaded. Start from a large square PNG for the sharpest favicon.